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A N

ESSAY

0 N T H E

MEDICINAL PROPERTIES

O F

FAcrir lous airs.

WITH AN

APPENDIX,

ON THE NATURE OF BLOOD,

B Y
TIBERIUS CAVALLO, F.R.S,

L O N D O Ns

PRINTED FORTHE AUTHOR,

And fold by C. Dilly, in the Poultry 5 P. Elmslt^,

and D. Bremner, in the Strand, — 1798.

PREFACE.

IT Is not quite forty years fince the ar-
tificial aerial fluids began to be admi-
niflered as remedies to the human body.
The uncertainty, and the errors of the
early applications, rendered the progrefs of
the practice flow and doubtful ; nor has the
experience, or the fuccefs of recent and
more numerous practitioners, been fuffi-
cient to determine the precife power of the
aerial fluids, or to diflipate the doubts which
are ftill entertained concerning their ufe.

The defire of extricating the fubjedt
from the conflidl of contrary opinions, efta-
blifhed prejudices, and oppofite interefls,
has induced the Author, perhaps too
hafl:ily, to publifh the prefent work, which,
in every fcnfc of the word, deferves the
epithet of imperfeft. But he hopes that
the importance of an object fo highly in-

A a terefling

iv PREFACE.

terefting to the human fpecies, may palliate,
if not juftify, the imperfedlions of the per-
formance, which might, perhaps, have been
lefs excufable in other fubjedis.

To exhibit a concife view of afcertained
fafts, to feparate them from fuppofitions and
hypothefes, and to point out the ways of
inveftigating the farther ufe of faditlous
airs, has been the Author's principal aim
in the compilation of the prefent Effay.

In the courfe of his inquiries, he has
frequently found caufe to admire the in-
genuity, the caution, and the perfeverance
of feveral gentlemen, who either have ad-
miniftered the aerial fluids, or have other-
wife exerted themfelves in the promotion
of their ufe. Yet he ha^ taken particular
care to avoid paying them any compliments,
or even making frequent ufe of their names,
left his defire of promoting the fubjecl
fliould be apparently converted into an en-
deavour of promoting the intereft of certain
practitioners.

The firfl four chapters contain fuch fads
as may be of theoretical ufe in the applica-
tions

PR E F A G E. V

tions of aeriform fluids, and in the invefti-
gation of their adion, independent on mer
dical cafes. The fifth chapter exhibits a
concife view of the modern theory of aerial
fluids, and of the procefles that are princi-
pally depending thereon, fuch as refpira-
tion, combuftion, &c. The fixth and fe-
venth chapters fhew the pradical applica-
tion of thofe fluids by way of remedies to
the human body ; and this praftice is ex-
emplified in the eighth chapter, in which a
feledl number of authentic cafes is related.
The ninth, or lafl: chapter, contains feveral
praftical remarks, hints, &c. which could
not be conveniently inferted in the .pre-
ceding part of the work,

Laftly, a differtation on the nature and
properties of blood has been added by way
of Appendix, that fluid being evidently and
principally concerned in refpiration, and in
the general dependance of the animal ex-
iftence on the aerial fluids.

By the mixt ufe of the old and the new
chemical names in various parts of the
work, the author imagines that his meaning

may

vj P R E F A C E*

may be rendered lefs equivocal, and more
generally intelligible ; for at a time when
the old names are not quite difufed, and
the new chemical nomenclature not uni-
verfally underftood, it is difficult to de-
termine whether the greateft number of
readers may remain fatisfied with the ex-*
clufive ufe of either.

Wells Street^
January the 8th, 1 798,

CONTENTS.

Chap. !• HT^HE principal Properties of
thofe Airs^ or permanently elaf-^
tic Fluids, which have been
applied as "Remedies to the Hu-
man Body - - page i
IL Fa6ls concerning the Refpiratiom
of Common^ and of Oxygen^
Airs - - - 22

III. Phcenomena arijingfrom breath-

ing other Aerial Fluids, befdes
the Common and the Oxygen
Airs - - - 40

IV. Phcenomena arifngfrom the Ap-

plication of the above -mejitioned
elajiic Fluids to other Parts of
the Animal Body befdes the
Lungs - - " S^
V. theory of the Nature of Aerial
Fluids, and of Refpiration 58

Chap,

via

CONTENTS.

Chap. VI. A general Idea of the Applica--

tion of Aerial Fluids for the

Cure of Diforders incident to

the Human Body - page 88

VII. Of the particular Adminiflration

of Aerial Fluids in different

Diforders - - 114

VIII. Medical Cafes in which Aerial

Fluids were adminijlered 1 49

IX. Tragical Remarks^ Hints, &c.

202

APPENDIX.

On the Nature of Blood - - - 227

AN

AN

ESSAY

ON THE

MEDICINAL PROPERTIES

OF

FACTITIOUS AIRS.

CHAPTER I.

T!he principal Propter ties of thofe Airs, or
permanently elajiic Fluids ^ which have been
applied as Remedies to the Human Body.

THE philofophical inveftigations of
the two laft centuries, and particu-
larly of the prefcxnt age, have afcertained
the exiftence of various elaftic fluids, ana-
logous to comnnon air, v/ith refped: to ekf-
ticity and invifibiiity ; but otherwife eflen-
tially different from it, as alfo different froin
each other i fach are the dephlogijiicated air,
or vital air^ or oxygen air j the phlogijlicated
air 9 or gas azote-, th^fxedair^ or carbonic acid

2 Medicinal Properties of
gas-, xhQ injlammable air, Qxhydroge7i gas\ the
nitrous gas. Sec. But as of all the different
airs five only appear to be applicable to the
human body, viz, the common, the oxygen,
the azotic, the carbonic acid, and the hy-
drogen airs, we ihall not therefore extend
our notice to any other fort of elaftic fluid ;
nor fhall we defcribe more than the prin-
cipal properties of thofe five ; viz. fuch pro-
perties only as may be ufeful to elucidate
their adlion on the human body.

OftheCommonyOrAtmofphericalAir.

That invifible elaftic fluid, which fur-
rounds the earth, and in which we live, is
indifpenfably neceflary to animal life, to
combuftion, and to other proceflTes. No
animal caa live, nor can any combuftiblpr
body burn, without air. For either purpofe
the atmofphericalair is more or lefs ufeful
in proportion to its purity.

When common air is mixed with another

particular fort of air, called nitrous gas, a

diminution of bulk takes place, which is

proportionate to the purity of the air ; the

^ pureft

pACTJTious Airs. 3

purefl: air being diminifhed moft, and vice
verfa; {o that very impure air fuffers no
diminution. Hence the quality or good-
nefs of comn!ion air may be afcertained by
mixing a certain quantity of it with a de-
terminate quantity of nitrous air, and then
meafuring the dirainution of bulk that
enfues. The inftrument in which this ope-
ration for afcertaining the purity of the air
is made, has been called an eudiometer.

The purity of common air is not the
lariie in all places, nor is it conflant in the
fame place at all times. The variation in
the latter cafe i^ much more confiderable
than in the former ^ yet, upon the whole, it
is not very great. If in the ufual ftate of
the atmofphere, and in places that are
reckoned healthy, 100 parts or meafures of
common air be mixed with an equal quan-
tity of nitrous air, their bulk, after the
mixture, will be found, inftead of 200 parts,
to be between loo and 120, more or lefs,
according to the time of the year, lituatiori
of the place, ftate of the atmofphere, &c.
B 2 But

4 Medicinal Properties of

But in caves, mines, crowded rooms, hof-
pitals, work-fhops, and the like, the air is
lefs pure ; yet even in this cafe the dif-
ference, as indicated by the teft of nitrous
air, is but trifling 5 excepting indeed thofe
places in which the communication with
the external air is abfolutely or almoft en-
tirely interrupted *.

Notwithstanding the fmall differ-
ence which is manifefted by this method of
trying the purity of common air, it is how-
ever evident, from the oppreliion which is
felt in certain inflances, and the reviving
effed: which is experienced in other cafes,

* Dr. Prieftley having dined one day in company
with eight or ten perfons, in a large and very lofty
room, and happening to go out of the room for a fhort
time, was, on his return, ilruck v/ith the offenfivenefs of
the air, and his curiofity prompted him to afcertain the
degree in which" the air was injured. On trial he found
that 100 parts of that air, with 100 parts of nitrous air,
were reduced to 131 parts; whereas the like experiment
being performed with the air of a well-ventilated room
^f the fame houfe, the 200 parts of mixt aerial fluid were
reduced to 125 parts.

that

Factitious Airs. 5

that the human lungs are fenfibly afFeded
by the fmalleft diiFerences in the purity of
the air. But it is neceffary to remark, that
noxious particles are frequently fufpended
in common air, which do not alter the ef-
fect: of nitrous gas upon it, though, at the
fame time, they render it very offenlive to
animals.

Considering the variety of vapours,
minute bodies, &c. that are continually
fcattered through, and float in, the air, the
atmofphere muft be looked upon as being
always contaminated by the prefence of
minute animal, vegetable, and even mineral,
particles -, — of bodies, in fhort, that are fo-
reign to, or unconnedted with, the nature of
air.

The quality of common air is not al-
tered by merely heating or cooling *, or by

* Every degree of Fahrenheit's thermometer rarlfies
or increafes the bulk of common air, by about -^j^ part
pf the whole.

B 3 ^ keeping.

6 Medicinal Properties of

keeping, or by being for a time loaded
with the vapour of water, nor by rarefac-
tion or condenfation i but it is contaminated
principally by refpiration, by combuftion,
by the fermentation and putrefadlion of ani-
mal and vegetable bodies, by the calcina-
tion of metallic fubftances, by the prefence
of vegetables when they are not under the
influence of the fun's rays, and by the ad-
mixture of every other gas, or permanently
elailic fluid, except the oxygen.

When the com.mon air is completely
contaminated, or rendered unfit for com-
buftion and refpiration, it is (according to
the prefent nomenclature) called gas azote ^
whereas it was formerly called phlogiJiicate4
air.

Vitiated air is capable of being meli-
orated various v/ays, and the methods of
effeding it may be diftinguifhed into na-
tural and artificial. I'he natural m.eans are
far from being known to their full extent -,
but the vegetation of plants, in certain cir-

cumftances.

Factitious Airs. 7

cutnftances, and the contaft of water, as ia
rains, dews, &c. are two very powerful
corredtors of contaminated air. Whether
thofe and other natural means, are fufficient
to preferve the atmofpherical air nearly in
the fame degree of purity, or whether that
degree be conftantly undergoing a gradual
change, fo as to render the air either con-
tinually better or worfe, is a very intereft-
ing queftion, but it can only be anfwered
by the philofophers of future generations.
For my part, I am led to fufped: that the
purity of the air is fubjed: to a periodical
fluctuation, or to an alternate increafe and
decreafe for an uncertain number of years.

Ventilation, and whatever promotes
ventilation, does nothing more than remove
vitiated air from thofe places in which it is
generated, and difperfe it through the at-
mofphere.

The artificial methods of correffing vi-
tiated air are few and imperfeft. Ventila-
tion, by means of bellows and other ma-

B 4 chines.

8 Medicinal Properties of

chines, is the moft efficacious, and at the
fame time the moft pradlicable way of im-^
proving the air of hofpitals, fick rooms,
prifons, &c. n)iz, by removing the vitiated,
and introducing a frefh current of purer air.
A fire purifies the air of certain places, only
by promoting the ventilation or circulation,
and by drying the moifture ; but the air
which has palled through the fire muft not
remain in thofe places, otherwife the injury
will be infinitely greater than the advantage.
It has been confidently aflerted, and denied,
but it is now with limitation believed, that
the vapours of nitrous, or of marine acid,
will diveft common air of the poifonous
effluvia of contagious diforders; hence thp
vapours of thofe acids are now frequently
difperfed through the air of hofpitals, crowd-
ed fhips, &c. When noxious vapours are
merely fufpended in the air, as it often takes
place in feveral natural and artificial pro-
ceffes, then reft alone, or at moft a flight
agitation in water will be fufficient to pu-
rify the air. By the admixture of oxygen
gas, a quantity of common air may be imr

proved

Factitious AirsI 9

proved to almoft any degree ; but the me-
thod is difficult and expenfive 5 hence it can
only be ufed with limitation in certain cafes,
which will be fpecified in the fequel.

Of the Depblogijiicatedy or Oxygen Air^

THE oxygen is a fort of aerial fluid,
that poiTeiTes the ufeful properties of com-
mon air in a much more eminent degree; wsr.
it affifts combuftion and animal refpiration
for a much longer time, and v/ith fuperior
energy. When a lighted candle is intro-
duced into a veflel full of oxygen air, its
flame becomes larger, and furprifingly
brighter than in common air. Its heat is
likewife increafed to a very great degree.

This air is not found pure or unmixed
in nature, but it may be extradled from va-
rious fubftances by means of artificial pro-
cefTes. The leaves of plants, indeed, yield
a confiderable quantity of it whilft they are
expofed to the light of the fun; but the
oxygen air which is thus produced, mixes

with.

lo Medicinal Properties of

with, and is difperfed through the circum-
ambient air as foon as it is generated ; fo
that the air contiguous to the plants is fel-
dom fenfibly better than that of the neigh-
bouring country.

By the addition of nitrous air the oxygen
is diminiflied much more than common air.
When loo parts of good oxygen air are
mixed with an equal quantity, viz, lOO
parts, of nitrous air, their joined bulk will
not exceed 50 parts, the other 150 parts
having loft the aerial form. Nor is this
the utmoft degree of diminution that can
be produced; for if 100 parts of the pureft
oxygen that can be procured, be mixed with
twice its quantity of nitrous gas, almoft the
whole bulk of elaftic fluid will difappear ;
at moft, the reliduum will not exceed five
or fix parts. By putting a lighted candle
into a vefiTel full of any fpecies of refpirable
air, and obferving the efFedl of that air on
the flame, one may eftimate the degree of
its purity near enough for feveral pur-
pofes.

The

Factitious Airs. ii

The following are the principal methods
of procuring this air. The green leaves of
vegetables, when placed in a glafs receiver
full of, and inverted in fpring v^ater, and
thus expofed to the dired: rays of the fun,
yield a confiderable quantity of oxygen air,
which afcends to the upper part of the re-
ceiver, and may be eafily removed from it
for ufe. One hundred leaves of Indian crcfs,
najiurtium Indicumy in a gallon of fpring
water, will, in about three hours expofure
to the fun, yield about ten cubic inches of
oxygen air, not indeed quite pure, but yet
vaftly better than common air. I do not
know of any plant whofe leaves produce
this fort of air in greater abundance.

There are feveral fubftances from which
oxygen air may be extracted by the adlion
of heat or of acids • but thofe which upon
the vv^hole yield it in greateft plenty, and
are fit to be ufed, are laltpetre or nitre, and
the metallic calces.

One

12 Medicinal Properties of

On'E ounce of nitre, by remaining ex*
pofed to a full red, or rather a white, heat
in an earthen retort for about four or
five hours, will give between 700 and
8cx) cubic inches of oxygen air, which
is not equally good in every period of the
procefs, but at a medium it is fuch that
if ICO parts of it be mixed with 150
parts of nitrous air, the whole will be re-
duced to about 100 parts. This oxygen
gas contains a quantity of nitrous acid in
the form of vapour, and therefore, when it
is to be ufed for refpiration, the acid vapour
rnufl be previoufly feparated from it, which
may be done by agitating the air in an al-
kaline lixivium, or at leaft in lime water.

If an ounce oi mercuriiis precipitatus per
fe be expofed to a barely red heat in a
glafs veffel, it will yield at leafl 66 cubic
inches of very good oxygen air.

Red precipitate of mercury, when treat.-
ed in the like manner, does alfo yield a
confiderable quantity of this fort of air.

The

Factitigus Airs. 13

The adion of a red heat alone, or of
vitriolic acid and a moderate degree of heat,
expels from minium, or red lead, about tQn
or twelve times its bulk of oxygen, mixed
with about one third of carbonic acid, air j
tlie latter of which may be feparated from
the form_er by waihing in linie water. If
the red lead be previoufly moiftened with
nitrous acid, and then llrong vitriolic acid
be poured upon it, a greater quantity of
oxygen gas will be. obtained in a fliorter
time, and even without the application of
heat.

This fort of elaftic fluid may be alfo ob-
tained in fmall quantities from feveral other
metallic calces j but the mintral called man^
ganefey gives a great quantity of it in an
eafy manner ; it is at the fame time a very
cheap article, fo that, upon the whole, man-
ganefe is at prefent the mofc eligible fub-
ftance for the purpofc of procuring oxygen
air.

Manganese

14 Medicinal Properties of

Manganese is not always of the fame
quality, and of courfe the elaftic fluid,
which is extraded from a given quantity of
it, is variable both in quantity and quality.
One ounce of good manganefe, free from
large calcareous particles, will, in a red heat,
yield more than two pints and a half wine
meafure, or about eighty cubic inches of
elaftic fluid, about one tenth of which is
carbonic acid, and the reft is oxygen gas.
By means of vitriolic acid and a gentle
heat, about an equal quantity of elaftic
fluid, nearly of the fame quality, may be
extracted from manganefe ; but in this cafe
fome acid vapours come over with it, which
muft be carefully waftied off^ in order to
render the oxygen air fit for refpiration.

The oxygen air is diminiilied to a much
greater degree than common air, not only
by the admixture of nitrous gas, but alfo
by all the proceflTes w^hich are known to
diminifli atmofpherical air ; and indeed
fometimes the whole quantity of oxygen
air is abforbed or deprived of its aerial

form.

Factitious Airs. 15

form. Thus, by refpiration, this air will
be entirely abforbed, excepting indeed that
part which is converted into fixed air.

Of Fixed Air^ or the Carbonic Acid Gas.

This gas> which is the heaviefl: of the
aerial fluids, is of an acid nature, but it
reddens only light blue vegetable colours ;
it cryftallizes with fixed alkali, and is pof-
fefled of a confiderable antifeptic power.
It is abfolutely incapable of affifting refpi-
ration and combuftion * ^ nor is it dimi-
niflied by nitrous air. It combines with
various fubftances, and is readily abforbed
by water, to which it communicates an
acidolous tafte and fparkling property. It is
alfo abforbed by, and precipitates the caU
careous earth in lime water, but when in
greater quantity, it again difiblves the cal-

* Even a mixture of one part of fixed, and eight
parts of common, air will extinguifn the flame of a
candle. See Cavendifh's paper, in the Phil. Tranfl for
1766.

careous

i6 Medicinal Properties of

careous earth in the water. It alfo diflblves
iron in water, and keeps it diffolved there-

in

This elaftic fluid is produced in a great
m?.ny natural as well as artificial proceiTes.
It is frequently found in fubterranean places,
efpecially in the vicinity of volcanos, and
hot fprings, v/here, on account of its great
fpecific gravity, it remains for a confiderable
time, unlefs it be removed by means of
ventilation, &c. It is contained more or
lefs in almoft all the mineral waters ; it is
abundantly produced in vinous fermenta-
tion. Refpiration, combuftion, and fome
other proceiTes, do likewife produce a cer-
tain quantity of carbonic acid gas. \l is
contained in a variety of mineral fubflances,
and particularly in calcareous earth, as chalk,
marble, &c. from which fubflances a great
quantity of that gas may be extra6led by
meins of heat or of acids *i the calcareous

* The £xed air which is contained in white marble
amounts to about one third part of its weight.

bodies

Factitious Airs. if

bodies remaining, after the lofs of that gas,
in a cauftic or acrid ftate ; fo that the cal-
careous earth, by being in a mild ftate whilfl:
it contains that elaftlc fluid, may be juflly
confidered as a neutral fait, coniifting of an
earthy bafls and an aerial acid.

Of the hijiammabk Air^ or Hydrogen Gas»

Inflammable Air is the lightefl of the
claftic fluids. It Is, as its name imports, a
combuftible fluid, which, like other com-
buftible fubfl:ances, maybe inflamed by the
contaft of an ignited body, and will burn
only when in contad with common, or oxy-»
gen, air.

TnotJGH this fort of elaftlc fluid be ab-
folutely unfit for refplration, it is not, how-
ever, io noxious as the carbonic acid. It
fuffers no diminution when mixed with
nitrous air. Its bulk is increafed of t^o-
part of the whole by each degree of Fahren-
heit's thermometer.

C Hydrogen

i8 Medicinal Properties of

HyDROGEN gas is abundantly produced
during the diffolution of animal and vegeta-
ble bodies ; hence it is often found to come
out of ponds, burying grounds, and other
places that contain animal and vegetable
matter in a ftate of decay. " This gas does
alfo frequently come out of the earth, where
inflammable minerals are contained, as in
coal mines, and mines of fulphureous me-
tallic ores. But in all thofe cafes the in-
flammable gas, by being much lighter than
common air, afcends to the upper regions
of the atmofphere as foon as it is produced,
and leaves the air, adjacent to the ground,
very little, if at all, infedted, excepting in
vaulted fubterranean places, where, indeed,
beiides its infecting the common air, it
fometimes takes fire and explodes, to the
great danger of the miners.

By means of heat, or of acids, this gas
may be obtained from almoft all forts of
bodies, whether they be vegetable, animal^
or mineral. But the greateft quantity of it
may be extrafted from iron, or from zinc,

3 H

Factitious Airs. ig

by means of diluted vitriolic acid; and
likewife from iron, by paffing the fteam of
boiling water over its furface, the iron being
red hot. When charcoal is treated in the
laft-mentioned manner, it likewife yields
abundance of a peculiar fort of inflammable
gas, called hydrocarhnate, which however
is mixed with a confiderable proportion of
carbonic acid gas.

Hydrogen gas has the property of
diiTolving and holding in fufpeniion, for a
longer or fhorter time, a variety of fub-
fiances, fuch as iron, charcoal, fulphur,
phofphorus, &c. from which circumftance
it acquires a variety of particular names as
wqW as properties. Hence we hear of the
phofphortc hydrogen gasy or phofphuret of hy-*
drogen ; of the fulphurtc hydrogen gaSy or
fulphuret of hydrogen, &c. ; hence alfo we
find that the hydrogen gas is not always of
the fame fpecific gravity, nor has it always
the fame fmell.

1%

20 Medicinal Properties of

It has been obferved, that the hydrogen
gas fometimes lofes its inflammability, and
degenerates into azotic air. This change
happens more frequently when the hydro-
gen gas is mixed with common air. The
caufe of this phenomenon has not yet been
fully afcertained.

For the fake both of brevity and of
perfpicuity I have omitted to mention the
fpeciiic gravities of the abovementioned
elaftic fluids in the preceding pages, and
ihall add them all together in the following
table, which contains their fpecific gravities
as well as the abfolute weight of a cubic
inch of each elafl;ic fluid.

The gravity of common air is conlidera-
bly aftedled by the variations of heat,
wind, purity, &c. fo that its fpecific gravity,
compared with that of water, has fome-
times been knovi^n to be as one to fix hun-
dred and fix, and at other times as one to
nine hundred and thirty-one*. The gra-

* Mullchenbroek, torn. IL §. 2059.

vities

Factitious Airs. 21

vities of other elaftic fluids are likewlfe fub-
jcdt to the fame variations. But the follow-
ing table has been calculated for a mean
and temperate ftate of the air, viz. when
its gravity is to that of water, as one to
eight hundred, when the height of the ba-
rometer is 29,85 inches, and when Fahren-
heit's thermometer is at 55*.

Names of the elafiic Their fpeci fie A .. r i r /

jr,/., -^ r^ •.■ Lubic Inch of each

in 7 roy (arains*

Common air - - i - -. - 0,31648

Azotic gas, orcom-1

mon air completely / o ^

diminiflied byni-(°'948 " 1 0,3
trous gas - - J

Oxygen air - - 1,0427 - - 0,33

Carbonic acid gas 1,5 - - - 0,475

The lighteft hydro-? @ ^r^^

gen gas ^ ^ \"^^^ ^^ ' ^1

WPiW II

22 Medicinal Properties of

CHAPTER IL

FaBs concerning the Refpiration of Common^
and of Oxygen, Air,

THAT the v/hole mafs of air which
fur rounds the earth is called the at-
mofphere^ that this atmofphere extends to
a coniiderable but unknown diftance above
the furface of the earth, that it decreafes in
denfity as it recedes from the earth, that its
motion is called wind, that it adls upon all
other bodies by its temperature, its weight,
and other qualities, that it abforbs vapours,
or keeps them fufpended, and fuch other
like properties of the atmofpherical fluid,
have been rendered fo common by the
prefent ftate of knowledge and of polite
education, as not to demand any particular
elucidation in this work ; we fhall, there-
fore, proceed immediately to enumerate the
phenomena which have been afcertained
relatively to the refpiration of common air,

upon

Factitious Airs. 23

upon which, as upon a folid bafis, we may
afterwards eftablifli the theory and the prac-
tice of applying the fadtitious airs to the
human lungs.

A CERTAIN quantity of air will fupport
animal life, or combuftion, but for a limited
time. If a lighted middle-fi^ed tallow
candle be confined in a veffel that holds
one gallon of common air, the flame will, in
a few feconds of time, begin to grow dim,
and it will be extinguifhed at the end of
about one minute; after this, if another
lighted candle be introduced into the fame
veffel, its flame will be extinguifhed imme-
diately.

If a man be confined in a veffel that
holds ten gallons of common air, he will
begin to feel an oppreffion, and a difficulty
of refpiration, at the end of eight or ten
minutes 3 this difficulty will gradually in-
creafe, and at the end of about half an
hour, reckoning from the beginning of his
confinement, he will lofe his fenfation,
C A his

24 Medicinal Properties of

his motion, and, prefently after, his life.
The fame effect will take place with other
animals, in a longer or fhorter time, propor-
tionably to their fize, nature, and difpoli-
tion of body.

In the ufual way of breathing, when
refpiration is performed in a natural and
eafy m.anner, a full grown perfon confumes
about five cubic i^^ty or thirty gallons and
a half, beer meafure, of common air per
hour.

' A MAN generally performs one infpira-
tion and one expiration for every feven or
eight pulfations of his arteries % therefore
reckoning, at a mean, eighty pulfations per
minute, a perfon may be faid to perform
eleven or twelve infpirations, and as many
expirations, in a minute. But refpiration
is quickened by various caufes ; 'viz, by
the quickening of the pulfe, by agitation of
the body, by heat, by furprife, by difeafes of
the lungs, by a rarefied atmofphere, and by
impure air. Thus when a man is confined

in

Factitious Aihs. 25

in a certain quantity of air, his refpiratlon is
quickened in proportion as that quantity of
air becomes contaminated ; he alfo takes
in and expels a greater quantity of air
at a time, in order to compenfate for the
want of purity. The fame quickening of
refpiration takes place on high mountains,
where the air is more rare than on the level
of the fea.

At a medium, about 30 cubic inches
of air are taken in at one infpiration, and a
quantity, nearly equal to it, is thrown out
at every expiration ; but a great deal of air
remains in the lungs, wind-pipe, and mouth;
fo that by a violent expiration after a natural
infpiration, a double quantity, viz, fixty
cubic inches of air, may be expelled, and
even then fome air necelTarily remains in
the lungs, wind-pipe, and mouth,

Th e air which has ferved for one infpi-
ration is not thereby completely contami-
nated, but it may be refpired again and
again. 350 cubic inches of common air

were

26 Medicinal Properties j/"
were confined in a bladder that was fur-
nifhed with a wooden tube ; this tube was
applied to the mouth of a healthy middle-
aged man, who, flopping his noftrils, en-
deavoured to breathe that quantity of air
as long as he poffibly could. After having
performed forty infpirations^ his ftrength
began to fail, and he was obliged to de-
lift.

Old perfons, people of a bad habit of
body, or labouring under difeafes, and fuch
as eat and drink immoderately, will conta*
minate the air much fafter than the healtbya
the iBoderate, and the young.

It has been afierted-^ that fome homaa
beings can live with a much fmaller quan*
tity of air than has been mentioned abovej,
and that divers have fome times been known
to remain under water ten or fifteen mi-
nutes, and even a longer time '^. It has

* See Beckman's Hiftory of Invention?^ article
Z)ivi72g-Bs!l} and Graelin's Reife Durch RLifslandj II,
p. 399.

been

Factitious Airs. 27

been llkewife difcuffed, whether fuch divers
were enabled to remain fo long under wa-
ter, and without air, by any particular con-
formation of the internal parts of their bo-
dies, or from long pradice and particular
artifices. But there are ftrong reafons for
difcrediting the above-mentioned aifertions.
The inaccurate way of reckoning the time
in fuch cafes, and the common fondnefs for
the marvellous, are in general the founda-
tion of fuch extraordinary reports. Upon
the whole, it will be found, that the moil
experienced diver can hardly remain with-
out air longer than a minute and a half;
but moll perfons will begin to feel a de-
gree of unealinefs in about half a minute's
time.

The air^ which has been completely con-
taminated by refpiration, is deleterious to ,
other animals, though fmall and young
animals will live a fhort time in it : it ex-
tinguifhes flame, is diminiChed very little
by nitrous air, contains about one- thirtieth
of carbonic acid gas, and is contracted in

bulk.

£8 MedicinaI Properties of

balk, the diminution being various, but
hardly ever exceeding one-lifth part of the
original quantity.

The deleterious quality of the air that
has been contaminated by refpiration is in
great meafure owing to the carbonic acid
gas, vs^hich is formed in the procefs of re-
fpiration ', and it is for this reafon that,
when an animal is confined in a veffel full
of refpirable air, he will be able to live
longer in it when feme lime-water is placed
in the veffel, than otherwife ^ becaufe the
lime-water abforbs the carbonic acid gas as
foon as it is generated. An animal will
likewife live longer in a veffel full of air,
when he is placed at the upper than at the
lower part of the veffel; becaufe in the
former cafe the carbonic acid gas will, on
account of its great fpecific gravity, fall to-
wards the lower part of the veffel, and will,
of courfe, be at a diftance from the body of
the animal.

The

Factitious Airs. 29

The refpiration of oxygen air is attended
v/ith peculiar phenomena. The oxygen,
like the common, air, is diminiflied by re-
fpiration ; but the diminution proceeds to a
much greater degree, for almoft the whole
quantity of elaftic fluid will be reduced to a
imall proportion of carbonic acid gas ; and
if the experiment be performed on lime-
water, the whole quantity of oxygen air
will difappear. By repeatedly performing
the experiment in this mannei^, it has been
found that a healthy middle-aged man will
entirely confume two gallons of pure oxygen
air in about five minutes time *. But in
this cafe the oxygen air is confumed fafter
than is neceflary for the ufual fupport of
life; and, in fad:, if the fame^quantity of it
be mixed with an equal quantity of azotic

* Amongit the various ways of ^producing oxygen
air, it frequently happens, as we have already hinted,
that acid vapours, or other volatile fiibftances, are
mixed with it; and in that cafe the animal which is
confined in it may feel an oppreffion on his lungs, or
he may even be fufFocated, when, by the tell of nitrous
gas, that air will actually appear to be much better than
common air.

gas.

30 Medicinal Pro^t^erties of

gas, it will then laft as long again, ijiz*
about ten minutes* It is therefore evident,
that as the azotic gas is abfolutely incapable
of affifting refpiration, the mixing of it with
the oxygen air produces no other eiFed: than
that of prefenting a fmaller quantity of
oxygen to the furface of the lungs in each
infpiration. It is for the fame reafon that
oxygen air is confumed fafter, and that
common air is vitiated fooner, when re-
fpired under an increafed, and flower when
refpired under a diminiihed atmofpherieal
preffure.

The air which is expelled from the lungs
after every infpiration, whether it be oxygen
or atmofpherieal air, contains, belides the
portion of carbonic acid gas, a confiderable
quantity of aqueous vapour, which, in cold
weather, is manifefted by its condenfation
as foon as it comes out of the mouth ^ for
air can hold in folution a much greater
quantity of water when hot than when
cold.

The

Factitious Airs. 31

The breathing of pure oxygen air is ge*
perally, if not always, attended with an in-
creafe of heat, cfpecially about the lungs,
and a quickening of the pulfe; but on fome
individuals thofe efFe(fts are increafed to fuch
a degree as to produce fevers, inflammation
of the lungs, and even coniumptions, w^hilfl
with other individuals they are moderate,
temporary^ and even falutary. But I fhall
endeavour to imprefs the reader's mind v/ith
a clearer idea of thofe phenomena, by fub-
joining a fhort account of the principal ex-
periments that have been perfornied rela-
tively to this interelling part of our fub-
jed.

Dr. Priestley is, as far as I know, the
firft perfon who had the curiofity of breath-
ing oxygen air. ** I \i2}i^^" fays he, *' gra-
*^ tified that curiofity, by breathing it^
*^ drawing it through a glafs-fyphon, and
*^ by this means I reduced a large jar full
** of it to the ftandard of common air. The
^* feeling of it to my lungs, was not kn^
^^ fibly different from that of common air,

'' but

32 Medicinal Properties ef

*^ but I fancied that my breaft felt peculi-
^* arly light and eafy for fome time after-
" wards *.**

The following experiment was perform-
ed, with great accuracy, before a philofo-
phical fociety of gentlem.en, at Dr. Hig-
gin*s houfe, in the year 1794. — Nineteen
pints of pure oxygen gas were put into a
receiver which flood inverted in lime-
water. A tube proceeded from the upper
part of the receiver to the mouth of the
experimenter, a healthy man of about
twenty-two years of age, who, after hav-
ing accurately flopped his noilrils, and hav-
ing expired as much air from his lungs as
he poffibly could in a bent pofture of the
body, took the end of the tube in his
mouth, and began to breathe the oxygen
air in a natural and flow manner, during
which the receiver was permitted to play
freely up and down in the lime-water, in
order to prevent any increafe or decreafe of

* Experiments on Air, &c; vol. ii. p. 102.

preflure

Factitious Airs. 33

preffare on the lungs. An affiflant was
employed to keep the lime-water in conti-
nual agitation, in order to promote the ab-
ibrption of the carbonic acid air that was
formed in the courfe of the experiment.
The bulk of oxygen air was vifibly dimi-
niflied at every infpiration, and the lime-
water became turbid. The v/hole of the
oxygen air was confumed in fix minutes
time, and the experimenter flopped only
V when the lime-water came to his mouth.
" During the refpiration bis pulfe (which,
** previous to the experiment, was only
*' fixty -four) quickened to ninety beats in a
** minute, and was confiderably increafed
*^ in fulnefs and flrength -, but he felt no
*^ inconvenience whatever.

^ The veffel being immediately charged
" again with nineteen pints of gas, he re-
*^ fpired thefe alfo, and confumed them en-
" tirely in fix minutes. His pulfe was in-
" creafed to 120 beats in a minute, and
** was vigorous withal. He felt no in-
*^ convenience, but had a fenfe of unufual

D /* warmth

34 Medicinal Propert'ies of

" warmth in his lungs. In one hour after
" the experiment his pulfe returned to
*^ fixty-four *;'

Dr. Bed does found the breathing of
oxygen air extremely hurtful. " To my own
** lungs," y2y/j he^ '* it feels like ardent fpi-
" rit applied to the palate j and I have
** often thought I could not furvive the in-
" fpiration of oxygen air, as it is driven
** from manganefe by heat, many mi-
" nutes -f."

A SINGLE infpiration of oxygen air may
be kept in the lungs much longer than an
infpiration of common air.

When oxygen air is mixed with com-
mon air, and is then breathed in that di-
luted ftate, the lungs are lefs afFeded with

* Minutes of the Society for Philofophical Experi-
ments and Converfations, page 146.

t Confiderations on the Medicinal Ufe of Fa£litious
Airsj vol. i. p, 14,

the

Factitious Airs. 35

the fenfatlon of heat, nor is the pulfe
quickened lb much as v/hen pure oxygen is
ufed ; yet in this diluted ftate the oxygen
air has been found beneficial in a variety of
cafes, which will be mentioned in the fe-
quel. We fhall likewife mention the pro-
portion of the two elaftic fluids, which has
been found to anfwer beft for each parti-
cular cafe ; but in the prefent chapter it
will be neceffary to ftate the efFed: which
the breathing, or the adion, of oxygen air
has been obferved to have upon particular
parts of the animal body, whence proper,
cofijedlures may be formed of its general
ufe in the animal economy, and of its ap-
plication for the cure or alleviation of par-
ticular diforders.

That oxygen air is a powerful ftimulus
to the lungs, has been evinced by various
experiments, but by none better than the
following, which has been repeated with
equal fuccefs by different perfons : — Some
young rabbits were kept under water till
every appearance of life, and even a hope

D 2 of

36 Medicinal Properties of

of recovery, had vanlflied ; they were theit
withdrawn, and oxygen air was forced
through the mouths of fome of them into
their lungs, whilft a fimilar operation with
common aii' was performed on the others t
the latter remained dead, whilfl: the former
recovered. Young dogs and kittens were
fubjeded to the hke experiment, the ge-
neral refult of which was, that the oxygen
air brought them to hfe where common
air proved ineifcd^uaL Animals thus ap-
parently deprived of life have frequently
revived by only being placed in a veiTel full
of oxygen air, without forcing it into their
lungs. From this fadt we derive a power-=
ful method of reftoring fufpended anima-*
tion. •

Rabbits, dogs, kittens, and birds, have
been often confined in veffels full of oxygen
air, and have been fuftered to remain in that
quantity of air for various lengths of time.
It has been conftantly obferved, that they
live longer in that, than in an equal quan-
tity of common air. But whenever the

experiment

Factitious Airs. 37

experiment has been protra(^ed to a certain
lenjjth, it has almoll always been attended
with illnefs, with a ftrong inflammation^ and
even with death. The diffedtion of the
animals that have been thus oxygenated, has
principally exhibited the following pheno-
mena .:

The lungs appear of a florid red coloui:,
often marked on the edges with figns of
mortification ; the heart appears of a florid
red colour ^ the pleura is generally in-
flamed ; the colour of the liver, kidneys^
and the blood-veffels of the mefentery, is
more inclining to red than is otherwife
known to be; their blood coagulates fooner;
their mufcles are more vigorous, and lliew
iigns of fl:ronger irritability.

xA-NixMALS that have breathed oxygen
air, previoufly to their being immerfed in
water, will not die fo foon as thofe which
have breathed common air only. The
quantity of j^irer air, which remains in the
lungs of the former, is what in great mea-

D 3 fure.

38 Medicinal Properties of

fure, if not entirely, contributes to the pre-
fervation of their lives.

After having defcribed^in the preced-
ing paragraphs, the principal phaenomena,
which are produced by the refpiration of
pure, or nearly pure, oxygen air, it will be
hardly neceffary to add, that a mixture of
common and oxygen airs, or of azotic and
oxygen airs, muft produce phenomena ana-
logous to thoie which have been men-
tioned above, but nearly proportionate to
the quantity of oxygen air which is con-
tained in the mixture. There is, however,
a remarkable circumftance, which mull be
carefully attended to, as being of the ut-
moft confequence in the application of
oxygen air to m.edicinal ufes. This cir-
cumftance is, that whilft the refpiration
of pure oxygen air, or of fuch air as con-
tains a great proportion of oxygen, is at-
tended with inflammation and other bad
confequences, the refpiration of common
air a little improved by the admixture of a
moderate proportion (as for inftance, one-

15th,

Factitious Airs. 39

15 th, or even one -20th) of oxygen air,
is attended with remarkably falutary ef-

The inhalation of fuch diluted oxygen
air, or we may call it improved atmofphe-
rical air, for about lo or 15 minutes a
day, has been found to produce a florid
colour in the face, to conciliate fleep, to
ftrengthen the organs of digeflion, to pro-
mote circulation, to ftrengthen the pulfe,
.&c.

However ftrange and unaccountable
thofe effedts may at lirft light appear, efpc-
cially to thofe who are not converfant in
philofophical inveftigations, the fadls are
certainly true, and a fimple refledion may
contribute to diflipate the wonder ^ namely,
that people of all defcriptions, but efpe-
cially fuch as are weak and emaciated,
derive a confiderable degree of exhilara-
tion and improvement by a fhort excur-
fion out of a town, or of a houfe, when
the fuperior purity of the country air,

D 4 above

40 Medicinal Properties of
above that of the town, is not equal to
that which is produced by mixing com-
mon air with even one-twentieth of its
bulk of oxygen air. But we fhall have oc-
cafion to notice this circumftance again in
the fequel.

CHAPTER III.

P hcenomefta ari/ing from breathing other
aerial Fluids^ hefdes the Common and
the Oxygen Airs.

IT has aheady been noticed^ that of the
various forts of elailic fluids, two only,
n)iz. the common and the oxygen airs, are
capable of aflifting refpiration, from which
it may be naturally deduced, that by the
admixture of any other gas, either of thofe
two will be rendered lefs refpirable in dif-
ferent degrees. But this diminifhed good-
nefs of the refpirable airs, this mixture of

refpirable

Factitious Airs. 41

refpirable and unrefpirable aerial fluids, has
proved beneficial in a variety of medical
cafes ; hence many experiments have been
made for the purpofe of afcertaining the
mixtures that are more applicable to any
particular cafe, and like wife the phseno-
mena which' arife from the refpiration of
thofe mixed gailes,

I WOULD not be underftood to affert or
think that the adtion of the unrefpirabk
gaffes conlifts merely in lowering the qua-
lity of common air, or of oxygen air ; for
that purpofe could be more commodioufly
anfwered by breathing a certain quantity of
common air longer than in the ufual waVv
The fadt is, that, belides rendering the
common or oxygen air lefs refpirable, each
particular gas imparts peculiar and remaark--
able properties to the mixture, which mix-
tures ar^ of courfe applicable to particular
cafes. With refpefl: to thofe mixtures,
much has already been afcertained ; but a
great deal more remains to be examined and
tried under a variety of circumftances, to

w^hich

42 Medicinal Proplrties of

which objed we muft look forward with
anxious expeftation.

It has been repeatedly afferted and de-
nied, that pure and unmixed hydrogen, or
inflammable gas, may be refpired with im-
punity for a confiderable time, and many
experiments are related to prove each of
thofe contradictory affertions. The equi-
vocal refults of thofe experiments arife from
two caufes, viz. from the variable nature
of the gas, and from the different quantity
of common air, which remains in the lungs,
Eitouth, &c. of the animals that are fub-
jedted to fuch experiments.

Inflammable gas, in the common
way of producing it, is feldom very pure ;
but even when that is the cafe, its coming
into contadt with the lungs is naturally pre-
vented by the common air, which remains
in that organ previoufly to the application of
the inflammable gas, the latter being much
lighter than the former. By a flrong ex-
piration in a bent pollure of the body, the

commoa

Factitious Airs. 43

common air may, in great meafure, be ex-
pelled ; but even in that cafe a certain
quantity of it unavoidably remains in the
mouth, wind-pipe, &c.

Of the different forts of inflammable
gas, that v^hich is obtained by pafling the
fleam of water over red hot iron feems to
be the leaft oiFeniive. Next to this is the
gas which is obtained from iron and diluted
vitriolic acid. The other fpecies are more
variable in their quality ; but they are all
incapable of affiiling refpiration ; and if a
perfon v^^ill carefully expel as much air
from his lungs as he poffibly can by a
forced expiration in a bent pofture, and
will then apply his mouth to a veffel, or to
a tube that communicates with a veffel, full
of pure inflammable gas, keeping his nof-
trils flopped at the fame time, he will find,
after about three or four infpirations, that
the florid colour of his face is vanifhed, and
Ris flrength is fo far diminifhed as to pre-
vent the profecution of the experiment.
Having myfelf been more than once wit-

nefs

44 Medicinal Properties of

nefs to this experiment, I have always ob-
ferved an evident change of colour in the
face of the experimenter after the i^Qoi^^
infpiration. — The gas had been extraded
from iron and diluted vitriolic acid*

Inflammable gas may be rendered
lefs noxious by agitation in water,

V/hen this gas (meaning that which is
obtained from the vapour of water and red
hot iron, or from iron and diluted vitriolic
acid) is mixed with about an equal quan-
tity, or even a fmaller proportion of com-
njon air, it may then be breathed with
iafety for a confiderable time ; and it is
remarkable, that the lungs are aifeded by
it with a peculiar feniaticn of levity. This
lingular property has rendered it ufeful and
beneficial in inflammations of the lungs,
convullive coughs, &c. where the object is
to diminifli the irritability of the parts af-
feded. During this operation the face
will be found to grow dark or livid, but the
natural colour will be fpcedily recovered by
3 afterwards

Factitious Airs. 45

afterwards breathing the common air in the
uluai way.

The hydrocarbonate, viz, thatfpecies of
inflammable gas which is produced by
palling the fleam of water over the furface
of red hot charcoal, is much more perni-
cious to the lungs. Animals will die much
fooner m this than in the above-mentioned
fpecies of inflammable gas. Sometimes
two or three infpirations of pure hydrocar-
bonate are fufHcient to occafion the death,
of the animal.

The active quality of this gas is per-
ceivable even when diluted with 20 or
30 times its own bulk of common air.
A perfon who breathes it in that diluted
ftate for about a quarter of an hour, is ge«
nerally made lick and vertiginous ^ feeling at
the fame time a fenfation of cold through-
out his whole body ; his lips become blue,
the face livid, and the pulfe feeble, though
frequent; but the fenfibility of the lungs
is confiderably diminifhed by it, on which

account

46 Medicinal Properties- of

account it has been adminiftered in various
cafes with advantage to the patient. Some
patients, after the refpiration of* this di-
luted gas, have experienced fuch levity or
infenfibility about the region of the lungs,
as to remain for a time entirely free from
pain.

It is remarkable, that the licknefs, diz-
zinefs, or, in fhort, the bad efFedls of the
diluted hydrocarbonate, frequently come on
after the operation, and fometimes come on
and go oiFtwo or three times repeatedly, at
the interval of an hour or longer ; which
fhews that this fort of gas can hardly be
adminiftered with too much care and cau-
tion.

Pure carbonic acid gas is likewife very
pernicious to the lungs. Sometimes one
or two infpirations of it have been quite
fufficient to kill an animal; and, indeed,
animals will die in carbonic acid gas, and
likewife in hydrocarbonate, much fooner
than if they did not refpire at all, or if they

were

Factitious Airs. 47

were immerfed in water, which proves that
fome noxious principle is introduced by thofe
gaffes into the body.

Of the animals, thofe which have large
lungs in proportion to their bulk, and are
formed to live in the air, are fooner af-
fefted by this gas ; thus the birds have in
p-eneral been found to die Iboneft in car-

o

bonlc acid air ^ the dogs come next, then
the cats, then the amphibious animals^ and
laftly, the infeds *. If they are not left
too long in this gas, they will, in general^
revive, by being removed into the common
air. When they die in it they (hew no
ftruggles. By being frequently expofed to
this gas, the animals may be fo habituated
as not to be killed by it fo foon as others
that were never expofed to it.

The following are the appearances which
have been more commonly obferved on the
differed bodies of the animals that have
been killed by carbonic acid gas. — The
lungs are a little collapfed, (hewing a few

* Bergman de Aido Aereo^ fed. 26.

inflamed

4$ Medicinal Properties of

inflamed places. The right ventricle and
right auricle of the heart, the pulmonary
artery, the vena cava, the jugulars, and the
veffels of the brain, are turgid with blood;
but the pulmonary veins, the aorta, the left
ventricle, and l^At auricle of the heart, are
moftly flaccid. The mufcular fibres of the
body are found deprived of irritability, fo
that even the heart, extradled whilft the
body is ftill warm, fhews no figns of irrita-
bility ^.

Fishes die in a few minutes time, in wa-
ter impregnated with carbonic acid gas -f*.

When this gas is diluted with twice or
three times its own bulk of common air, it
may then be breathed for a certain time,
but not nearly fo long as the mild forts of
inflammable air ii milady diluted.

Pure azotic f^as is about as deleterious

o

as the iniiammable gas from iron and di-

* Bergman de Jcido Aereo, i^di. 26.
t Pricflley's Exp, and Obferv. vol. ii. fe£l, 13.
N° 3.

luted

Factitious AiR$. 4:91

luted vitriolic acid; yet the animals that
are confined in it until they appear to bfe
dead, will, on being Xyithdrawn, recover
more frequently than thofe which are coil-
fined in the inflammable gas.

The artificial gaffes have likewife Been
breathed in combinations of three or fbtfr
at a timci one of them alvi^ays being.eithdr
the common or the oxygen air ; but it does
not appear that thofe triple or quadruple
mixtures have been tried in a great variety
of cafes.

In the refpinhg of conlbihed gaffes, due
regard muft be had to their fpecific gra-
vitiesj as this clfcunlftance is often the
caufe of phs^nomena that are erroneoufly at-
tributed to other fources. The difference
between the fpecific gravities of the com-
ihon, the oxygen, and the azotic, airs, id
indeed trifling; but the inflammable and
the carbonic acid gaffes diflfer confiderably
from the refl:, and efpecially from each
other; the former being a great deal

E lighter.

50 Medicinal Properties of

lighter, and the latter much heavier, than
common air. If the inflammable, the carbo-
nic acid, and the common or the oxygen, airs,
be not well mixed together in a veffel, they
will remain feparate for a confiderable time
in their refpedive places, ^-oiz. the carbonic
acid air in the loweft part, the common in
the middle, and the inflammable in the
highefl: part of the velTel ; but even when
they are well mixed together, they always
/hew a tendency to feparate, fo that after a
ihort interval each of them will be found
lefs mixed in its refpedtive place.

It is hardly necefiary U, add, that the
fame peculiarity of fituation muft alfo take
place within the lungs, and that this is,
perhaps, the fole caufe which render^ the
carbonic acid gas more noxious than the
inflammable gas, and the heavy fort of in-
flamm.able gas, hydrocarbonate, more ofFen-
five than the lighter fpecies of it.

Factitious Airs. ^t

CHAPTER IV.

Ph(znomena arifing from the Application of
the abovementioned elajiic Fluids to other
Parts of the Animal Body bejides the
Lungs.

IT has been found that the pores of the
fkin imbibe and expel a fmall quantity
of air^ and it is faid> that in equal times
they will abforb a much greater quantity of
oxygen, than of common, or of any other>
air,

Dl P FE R iE N 1: forts of elaftic fluid Were fe-^
parately injedled into the cellular membrana
of animals, through incifions made in the
Ikin, and the apertures were clofed imme^
diately after. The appearances, as obferved
by Dr. Maxwell *, and confirmed by others^
were in general as follows :

* See his Thells, Edinburgh^ 178?.

E a CoMMoU

5^ Medicinal pRoPERtiEs of

Common air fwelled or puffed the ani-«
mal, rendered it uneafy for a day or two,
after which the fwelling began to decreafe,-
and vanifhed entirely at the end of about
three weeks.

Oxygen air fwelled the animal, and ren-
dered it fomewhat uneafy for a fhort time ;
the uneafinefs, however, foon vaniihed,
the animal became unufually lively, and the
fwelling difappeared much fooner than in
the cafe where common air had been ufed."

' *• ' A-zoTic gas- fwelled the animal, and ren-
dered it dull, by fuperinducing a fort of
ftupor, which, in a few days time, de-
generated into eohVu!ii6Sis, and at laft killed,
^the animaL-'--'*---^ ^-^'^ ^^^' ^■■-i-^^^-i ^

^ ^'^Garbonic acid 'gAs ^^a^ ^iiapMty ab-
"forbed, and feldom prcductd any flight and
temporary uneafinefs.

. '^t,8i; \y

Hydrogen gas fwelled the animal, pro-
duced heaviiiefs and fhiverings; but the

fwelling

Factitiou^S'Airs.- ; ; 5g

fwelling difappeared fooher than in the caft
of common air. ?

Mr. Girtanter is faid to have injedr-^
ed azotic gas into the jugular vein of a dog,
in confequence of which the animal died at
the end of twenty feconds. On opening
its thorax, the pericardium, and the heart,
the right auricle and right ventricle vv^cre
filled with black blood ; the left ventricle
was of its ordinary dark colour ; the heart
and mufcles had loft their irritability almoft
entirely. A iimilar experiment being made
with carbonic acid gas, inftead of azotic
gas, nearly the fame phsenomena took place..

Blood recently taken from the veins of
an animal, and expofed to the common air,
becomes of a bright red colour ; and if ex-
pofed to oxygen air, its colour will become
ftill brighter, and the oxygen air will be di-
minifhed, and partly converted into carbonic
acid air. On the contrary, if the bloo4
thus brightened, or the blood taken from
the arteries of an animal, which is well
E 3 knowri:

54 Medicinal Properties of

known to be of a florid red, be expofed to
any of the unrefpirable gaffes, its colour will
be darkened prefently, and a fmall part of
the elaftic fluid will be abforbed. It is to be
remarked, that thofe efFeds take place even
when an animal membrane, as a piece of
bladder, intervenes between the blood and
the refpirable or unrefpirable elaflic fluids *.
Even the colour of the flefhy parts is made
to incline more towards a florid red by the
adtion of oxygen air*

That the oxygen air adls as a ftimulus on
other parts of the body, as well as on the
lungs, is clearly proved by the following
often repeated experiment : A blifl:er being
formed on the hand, or a finger, by the ap-
plication of the ufual plaifi:er of cantharides,
the ikin was cut ofi\» and the hand was im-
mediately introduced into a veflfel full of
oxygen air : the confequence was, that the
experimenter felt a very acute pain. The
hand was then removed into a veffel full of

* Prieftley's Exp. and Obf. vol. III. i^di. 5.

carbonic

Factitious Airs. 55

carbonic acid gas, the aftion of which re-
moved the pain in a very (hort time. On
the hand being exppfed to the common ah*,
a degree of pain returned, and on being, as
at firft, placed in oxygen air, the pain be-
came acute.

The contadl of inflammable gas does
neither accelerate nor retard the putrefac-
tion of animal matter.

When the ftream of carbonic acid air is
ifTuing out of a fmall aperture, as that of
the tube of the phial in which this gas is
ufually produced from calcareous earth and
diluted vitriolic acid, if the mouth or nof-
trils be prefented to it, they will be affe6led
with a peculiar, and rather pleafing, pun-
gency.

This gas is pofleffed of confiderable an-
tifeptic power. And for this property, it is
adminiftered to the animal body either in-
ternally or externally, and feparate parts of
animal or ytgetable fubflances may be pre-
ferved in it for a confiderable time.

E 4 It

5P Medicinal Properties of

It is applied internally to the ftomach,
or externally, either in the aerial form, or
combined with water and other fubftances.
Many fluid or folid bodies derive their anti-
feptic property from their containing this
gas in confiderable quantity^ fuch are li-
quors in a ftate of vinous fermentation, ripe
fruit, certain mineral waters, &c.

Fruit may be preferved feveral days
longer in carbonic acid than in common
air. This is alfo the cafe with animal
fluids, or with pieces of meat that are not'
very large, but they are apt to loofe their
flavour. Large pieces of meat are faid to
have been preferved for feveral days longer
than in the ufual way, by only wafhing
them three of four times a day in water
ftrongly impregnated with carbonic acid
air.

Distilled water, or water that has
been deprived of its air by boiling, will, in*
forty days time, and in a temperate atmo-
fphqre, abforb, without needing any agita-

. . tion.

Factitious Airs. 57

tion, about xVth of its bulk of oxygen air,
whereas of common air it will abfoib about
the half of that quantity, viz. »Vth part. It
will abforb in a few hours time a quantity
of carbonic acid gas little greater than its
own bulk ; but a cold teq3perature and an
increafed atmofpherical prefTure will enable
it to abfprb a much greater quantity of
that gas. Of inflammable gas it will ab-
forb about as much as it docs of common
air, viz. -rV^h part of its bulk.

This abforption of elaftic fluids by water
is much expedited by agitation of the latter
in the former.

j8 Medicinal Properties of

CHAPTER V.

theory of the Nature of Aerial Fluids ^ and of

Kefpiration,

TH AT refpiration and life can not be
maintained without atmofpherical
air, is a fad: known to the philofophers of
the remoteft antiquity y but their ideas of
the ufe of air in refpiration were vague, and
unfupported by experiments. On the re-
vival of learning in Europe, and efpecially-
after the fixteenth centurv, the fcientific
inquiries of philofophers, phyiicians, and
chemifts, afcertained that the air was fub-
fervient to other natural as well as artifi-
cial proceiTes, befides refpiration ; and like-
wife that there actually exifted various fpe-
cies of air, fome of which were highly
noxious *. The progrefs and diffemination
of fcience gradually added new articles to

* See the works of Van Helmont and Dr. Mayow.
^ th^

Factitious Airs. 59

the ftock of knowledge relative to the aerial
fluids ; but the great improvements, the
furprifing difcoveries, w^hich have produced
a total revolution in this branch of natural
philofophy, were refer ved for the prefent
age, and are undoubtedly due to the labours
of modern philofophers.

It is entertaining to perufe the works of
authors previous to the late difcoveries, and
to obferve how near the ideas of fome of
them approached the modern theory of
refpiration. Hippocrates conlidered air as
one of the aliments of the body. Dr.
Mayow aiferts, that fome nitre, or aerial
fpirit of nitre, enters the body through the
lungs, and furniihes the animal fpirits at
the fame time that it communicates heat to
the blood*.

" Dr. White fuppofed that the Simu-
lating quality of the air is neceffary to keep
the heart in motion. Mr. Hewfon, obferv-

* See his work, printed at Oxford in the year 1674,
ynder the title of TraSfatus quinque MedicO'Fhyftci,

ing

6o Medicinal Properties of

ing that the blood has a more florid red
appearance in the left, than in the right,
auricle of the heart, concludes with faying,
that as the change of colour in, blood out of
the body is occalioned by the contadt of
air, fo it may be prefumed that the fame
change within the body is occaiioned by
air alfo, and that the change takes place in
the lungs.

Dr. Priestley formed a very ingeni-
ous hypothefis concerning the ufe of air in
refpiration, which he eftabliflied by a train
of well-condud;ed experiments on the then
prevailing phlogiftic theory. The princi^
pal law of this hypothefis is, that the air
ferves to abforb the fuperfluous phlogifton
from the blood through the lungs, and
that the more or lefs florid rednefs of the
blood depends on the diff^erent quantities of
phlogifton in it *. The phlogiflion, how-
ever, or principle of inflammability, is not

* For a full explanation of this hypothefis fee the
PoiStor's Exper. and Obf. vol. IIL feft. 5 ; or the Phil.
Tranf. vol.LXVL ; and likewife Dr. Crav^'ford's work
©n Animal Heat and Inflammation.

a realj^

Factitious Airs. 6i

^ real, but a fuppofed, agent in nature,wliich,
for want of better information, was applied
to explain moft of the phasnomena of com-
buftionjdecompoiition, and (by Dr, Prieft-
ley*s ingenuity) of refpiration. Bat the pre^
lent ftate of knowledge being, in confe«
quence of very recent difcoveries, fufficient
to account for the abovementioned phseno-
mena in a iimpler, and, of courfe, a more
natural way, the fuppofition of the phlogiftic
principle is become altogether fuperfluous,

Of this new or antiphlogiftic theory,
Vv'hich may be {cea at large in a variety of
recent publications, and of the difcoveries
which gave rife to it, I lliall briefly mention
fuch particulars only, as may be of ufe in
elucidating the acflion of the aerial fluids on
the human body. As for the fads upon
which its feveral parts are eftablifhed, and
like wife for the objeftions which have been
made to it, I muft refer the reader to the
works of other authors *.

* See Lavoifier's Elements of ChemiHry, Dr.Prleft-
ley's pamphlet, entitled, Experiments and Obfervations
relating to the Analyfis of Atmcfpherical Air, &c. ;
Fourcroy's Chemiftry, &c.

This

62 Medecinal PropertiSs of

This theory is at prefent almoft uriiver-
fally adopted by perfon« of the iirft rank in
philofophy, and daily experience is continu-
ally throwing nev/ light upon it; yet it
muft be confeffed that it is by no means
free from doubts and difficulties. It is in
confequence of thofe deficiencies, and on
account of the uncertainty, which is infepa-
rable from the nature of hypothefes, that I
have, carefully feparated the knowledge of
fad:s from the fuppofition of their caufes.
The former have been arranged in the pre-
ceding four chapters, and any perfon may
account for them in the manner he likes
beft; but it w^as deemed neceflary, at the
fame time, to add the moil fatisfadlory ex-
planation which can be fuggefted by the
prefent ftate of knowledge, and this ex-
planation will be found in the prefent
"chapter.

The fehfation of heat is fuppofed to be
produced by a peculiar fluid called t^e caloric^
or elementary heat ; a fluid extremely fine^
penetrating, and fo light that its weight can-
not

FAt:TiTious Airs. 63

not be eftimated. All forts of bodies are
expanded by the addition, and contracted
by the abftra6tion of caloric. The acceffion
of it to the human body produces the fen-
fation of heat, and the feparation of it pro-
duces the fenfation of cold. Thus when we
touch a fubftance which is of a lower tem-
perature, viz. colder than our bodies, that
fiibftance, by robbing us of a portion of
caloric, will excite the fenfation of cold 5 and
on the contrary, if the fubftance be hotter
than our bodies, it will excite the fenfation
of heat, by adding caloric to our bodies.

When a number of bodies of different
temperatures are put together, the fum of
their quantities of caloric will be difperfed
amongft them in fuch a manner as to rea-
der them all of the fame temperature, fo
that a thermometer will be found to indi-
cate the faj2ie precife degree of heat in any
one of them. But it muft be remarked^ that
though the temperature be the fame, yet
the abovementioned fum of elementary heat
;will not be divided equally amongft the

bodies.

©4 Medicinal PRopERf ies of

bodies, unlefs the bodies be of the faftitf
fort, as, for inftance, three or four parcels
of water, or of mercury, &c.; but fome
bodies will imbibe more and others lefs of
the caloric, in order to be raifed to the
fame temperature, or apparent degree of
heat; and this peculiar difpofition in any
particular body is called its capacity for
contairiing caloric* This property of bodies
may be rendered mo v:; intelligible by an ex-
ample or two. Suppofe that a pint of water,
at 1 00° of heat, be mixed with another pint
of water at 200° of heat, the heat of the
mixture will be nearly 1 50'', njiz, an arithme-
tical mean between the two temperatures ;
but if a pint of water at 100° of heat be
mixed w^ith a pint of quick filver at 50'' of
beat, the heat of the mixture will be found
;,jlo be 80°, ("Viz, greater than 75% which is
the arithmetical mean) which ihews tKdt
either the quickiilver or the water, has imr-
.bibed more than its equal fhare of caloric,
• in order to have its temperature raifed to
the common degree of fenfible heat. On
the other hand, if the degrees of heat be

reverfcd.

Factitious Airs. 65

teverfed, viz. tht water at 50' be rrjixed
with an equal bulk of quicklilver at 106%
the temperature of the mixture wdll be 70%
which plainly fhews, that water abforbs
more heat than quickfilver; and as the
difference between their original tempera-
tures and the temperatures of the mixture
in the firft and laft cafe is as two to three.
We therefore fay, that the abfolute heat of
mercury is to that of an equal bulk of water
as two to three; viz, " that the compa-
** rative quantities of their abfolute heat^
*^ are reciprocally proportionable to the
*^ changes v/hich are produced in their
^^ fenfible heats, when they are mixed to-
*^ gether at different temperatures "*/'

Similar experiments performed on a
variety of bodies fhew, that unequal quan-
tities of abfolute heat muft be communi-
cated to them in order to raife their tempe-
rature, or apparent heat to the fame degree.

* Dr. Crawford on Animal Heat and Inflammation ;
in which work a full explanation of the do6i:rine of heat
will be found, together with a table of the comparative
heats of different bodies.

F It

66 Medicinal Properties of

It is in confequence of their various ca-
pacities, that whenever bodies of different
fpecies are brought together, a change of
temperature is. generally produced. Thus, If
you mix fpirit of vs^ine and water, the mix-
ture will become hotter than the ingredients
were before. A much greater degree of
heat will be produced by mixing water
with vitriolic acid; and, on the other hand^
if fal ammoniac de diffolved in water, a
confiderable degree of cold will be pro-
duced.

In moft fubflances a total change in
their ilate of exiftence is produced by the
fuperaddition of caloric y thus water is gra-
dually changed from its folid ftate of ice,
into a fluid, and then into an elaflic fluid,
called vapour, by xht addition of different
degrees of caloric. And it mufl be re-
marked, that this change of fl:ate in bodies
is attended with a change of capacity for
containing caloric ; the lefs denfe flate con-
taining the greateft quantity of caloric*
Thus water in the fluid ftate contains lefs
3 caloric

Factitious Airs. 67

caloric than when it is reduced into vapour,
and more than when it exifts in the form
of ice.

The aerial fluids are fuppofed to be
combinations of certain fubftances with ca-
loric. Oxygen air confifts of a fubftance,
fui gefieris, which is called oxygen, com-
bined with caloric, and, in all probability,
with the matter of light alfo.

Azotic gas confifts of a particular fub-
ftance, called azote^ and caloric. Common
air coniifts of azotic gas and oxygen air, in
the proportion of 73 parts of the former to
27 of the latter. By a mixture of thofe
claftic fluids in the faid proportion, an aerial
fluid is formed exadly like the atmofphe-
rical air *.

Hydrogen gas confifts of a particular
Hibftance, called hydrogeriy and caloric. As

♦ In general the atmofpherlcal fluid contains a
variety of extraneous particles, but they hardly ^ver ex-
ceed the hundredth part of the w^Qle, and feldom
amount to that quantity.

F 2 for

68 Medicinal Properties of

for the particular fubftances which are fre-
quently found in the hydrogen gas, fuch as
phofphorus, particles of iron, &c. ; they
muft be confidered as extraneous matters
fufpended or diffolved in the gas, but not
eflential to its conftitution.

Carbonic acid gas confifts of a pecu-
liar fubftance, called carbon, or the con-
ilituent part of charcoal, and oxygen air, in
the proportion of k^zn of the former to
eighteen of the latter.

Water, which has long been efteemed
an elementary fubftance, incapable of de-
compofition, has been found to confift of
hydrogen gas and oxygen gas, in the pro-
portion of three of the former to feventeen
of the latter. By the combuftion of thofe
elaftic fluids water is actually formed j and,
on the contrary, water may be reduced into
thofe aerial fluids, by placing it,' under certain
circumftances, in contadt with bodies that
attradl one of it5 components, or by the
adlion of eledlricity *.

* See Fourcroy's Chemlftry, the third volume of my
Electricity, and the Phil. Tranf, for 1797, P. I.

Combustion

Factitious Airs. 69

Combustion confifts in the abforption
of the bafe of oxygen air, viz. the oxygen,
by bodies that are faid to be combuftible,
and fetting free both the caloric and the
light, which, as has been mentioned above,
are the two other components of oxygen
air. Agreeably to this definition, we muft
confider as combuftions not only the burn-
ing of coals and other fuel, as is ufually
done in our chimneys, but alfo the calci-
nation of metals, and refpiration itfelf,
iince in both thofe procefles an abforption
of oxygen, and an evolution of caloric,
take place.

If the calcination of a metal (v/hich is
now called oxygenation of the metal) is
carried on flowly, as by merely expofing
certain metals to the atmofphere, then the
caloric and the light, which is feparated
from the oxygen portion of the atmofphere,
is too little to affecS our fenfes, and we can
only obferve, after a certain time, that by
having abforbed a quantity of oxygen, the
metallic fubftance has loft its combuftibi-
F 3 lity

70 Medicinal Properties of

lity (liz. its attradion for oxygen) and
has affumed a different appearance, to-
gether with an increafe of weight. If the ~
oxygenation be carried on in a quick man-
ner, as when an iron wire is made very hot
in oxygen air, then both the caloric and the
light become manifeii.

When the metal has abforbed as much
oxygen as its nature admits of, it is then
faid to be incombuftible, or completely
oxydated. But if by any means the oxy-
gen be feparated from it, then the metallic
oxyde will be converted again into a me-
tallic fubftance fufceptible of combuftion.

In the combuftion of animal and vege-
table fubftances, which confift of various
component articles, the procefs is accom-
panied with peculiar phjenomena, which
vary with the nature of the combuftible,
the quicknefs of the combuftion, and other
circumftances. Thus in the burning of
wood, the oxygen of the atmofphere is ab-
forbed, the caloric and the light are difen-

gaged.

Factitious Airs. 71

gaged, the carbon of the wood combines
with a portion of the oxygen, and forms
carbonic acid gas, the evolved caloric con-
verts the aqueous part of the wood into
fteam, and fo forth.

A VARIETY of phsenomena may be ob-
vioufly explained upon the bafis of this
dodrine.

We may eafily comprehend why no fort
of combuftion can take place where no oxy-
gen air exifls j as alfo why every fort of
combuftion will proceed rapidly in pure
Oi^ygen air, and much lefs fo in common
air 5 for the latter contains only a fmall
proportion {viz. about one quarter) of
oxygen air. Thus may ojther procefTes be
eafily reconciled to, or explained by, this
theory. But it is now time to examine the
ph^enomena of refpiration.

The ufes of refpiration are various and
important. They may be divided into me-
chanical and chymical. Of the mechanical,

F 4 fuch

72 Medicinal Properties of
fuch as the voice, the cough, &c. no notice
will be taken in this work. The other ufes
principally confifl: in furnifhing the body
with aconftant fupply of oxygen, and pio-
bably in exonerating the blood of the
fuperfluous carbon and hydrogen.

In the procefs of refpiration a decompo-
fition of the air takes place in the lungs.
The blood, in its paflage through that or-
gan, abforbs the oxygen of the common air,
difengages the caloric, and leaves the azotic
gas, with a fmall reiidimm of oxygen air.
The blood, therefore, does not imbibe the
oxygen air, but the oxygen alone, viz, the
bafis of oxygen air, divefced of that quantity
of caloric which was neceffary to give it
the aerial form. The caloric which is fet
free in this procefs, by difperfing itfelf
through the body, keeps up its temperature,
and forms the origin of animal heat. How-
ever, this part of the theory which relates
to the formation of animal heat, is embar-
raffed with difEculties, which will be no-
ticed prefently*

The

Factitious Airs, 73

The carbonic acid gas, which is formed
in the procefs of refpiration, is fuppofed to
derive its origin from a quantity of carbon,
which, being difcharged from the blood,
combines with a portion of the oxygen
air.

The watery vapour which is expelled
with the air that is expired from the lungs,
is fuppofed to be formed in that organ by a
combination of oxygen with a quantity of
hydrogen, which is likewife difcharged from
the blood. But it is not unlikely that both
the carbonic acid gas and the water, inftead
of being formed in the lungs, may come out
of the blood, through the exhaling pores of
that organ, ready formed ; the blood having
originally received it in that ftate from the
chyle, &c.

The air then which is expired from the
lungs, contains a fmaller quantity of oxy-
gen air than it did before, but it con-
tains alfo fome carbonic acid gas, and fome

water.

74 Medicinal Properties of

water, in the form of vapour*. — 'Let us
BOW examine the different parts of this
theory.

It is evident, from the foregoing fads
and explanations, that the oxygen air is the
only fluid capable of aflifting refpiration and
combuftion, and that it is indifpenfably ne-
ceffary to animal life, fince the common air
is ufeful only on account of the oxygen it
contains.

* There are fome modern philofophers, who explaiii
the phaenomena of refpiration without admitting the ab-
forption of oxygen by the blood. The blood, they fay, in
palling through the lung?, acquires a vermilion red
colour, becaufc it depofits a portion of its carbonated hy-
drogen upon the air j and it becomes again dark in the
courfe of circulation, becaufe it combines v/ith a frefh
quantity of carbonated hydrogen. At the fame time the
oxygen of the common air which enters the lungs, by
combining w^ith the carbon and with the hydrogen,
forms the carbonic acid gas with the former, and the
v/atery vapour with the latter. — It may be eafily per^
ceived, that by only changing the name of carbon into
that of phlogillon, this explanation may, in a great
mcafure, be made to coincide with Dr. Prieftley's hypo-
ii:ens.

The

Factitious Airs. 75

The mixture of nearly one part of oxy-
gen air and three parts of azotic gas, which
forms the atmofpherical fluid, is, in all pro-
bability, the beft proportion of ingredients
for the maintenance of life ; fince we find
that with a fmaller proportion of oxygen,
not only the refpiration becomes unpleafant
and laborious, but debility, convulfions,
and other bad efFeds are produced; and
on the other hand, that bad fymptoms of
another fort are brought on by a greater
proportion of it, fuch as a preternatural
heat, feverifli pulfation, pains, inflamma«*
tions, &c.

The phenomena of refpiration and of
combuftion are not only analogous, but
they illuftrate each other in an admirable
manner. In atmofpherical air a candle gives
light fufficient for ordinary purpofes. In a
lef$ pure atmofphere the light becomes too
dim 'y and in pure, or nearly pure, oxygen
air, the candle will indeed give a much
brighter light ; but it will wafte fo very faft,
as not to laft perhaps the twentieth part of
the time it will in common air.

That

76 Medicinal Properties of

That the blood abforbs the oxygen of
the atmofpherical air in the adl of refpira-
tion, is a propofition which a variety of ex-
periments and analogies feem to prove be-
yond all doubt. When blood, recently taken
out of the veins of an animal, is enclofed in
a piece of bladder^ and is thus expofed to
common air, or to oxygen air, it acquires a
florid red colour, and part of the oxygen^
air is abforlDed. The fame thing takes place
within the body, i^iz. the air v^hich is ex-
pired contains a fmaller proportion of oxy.^
gen than it did before, and the blood which
returns from the lungs to the heart, and
thence proceeds through the arteries, is
found to have acquired a bright rednefs in
its paiTage through the lungs; it is there-
fore natural to conclude, that the blood has
abforbed the oxygen through the pores of
the thin membrane, which feparates it from
the air in the cells of the lungs *.

* This membrane is certainly much thinner th^in
common bladder. Dr. Hales conjedured the thicknqfs
of the former to be the thoufandth part of an inch.

The

Factitious x\irs. 'j'j

The probability of this conclufion is
corroborated by ftrong collateral proofs ^ as
by obferving that the arterial blood of ani-
mals that have been fuffocated, or that have
died for want of oxygen air, is far from be-
ing of its uHial florid red colour ; as alfo by
obferving, that when a quantity of blood is
confined in a veffel flill of air, the air is not
fo quickly contaminated or deprived of its
oxygen by the prefence of arterial, as by
that of venous blood. And it is even af-
ferted, that a quantity of blood taken out of
the carotid artery of a fheep, being confined
in a veffel full of azotic gas, improved the
gas fo as to render it, in fome meafure, fit
for refpiration, fo that fome oxygen muli
have been imparted to it by the blood ^.
This experiment defer ves to be repeated
with particular care.

The decompofition of air, and the ab-
forption of its oxygen in combuftion and
oxygenation of metallic bodies, are alfo ana-

* Medical Extracts, vol. I. p. 70.

logou«

yS Medicinal Properties of

logons to the phaenomena of refpiration, and
confirm the abforption of oxygen by the
blood in that procefs.

It is true that a fmall quantity of car-
bonic acid gas is found in the air in which
blood has been confined; but the formation
of this gas does not entirely account for the
diminution of the oxygen. Befides, it is
not improbable, as we faid above, that the
carbonic acid gas comes out of the blood
ready formed, at the fame ivmt that the
blood abforbs the oxygen.

By examining the courfe and ftate of the
blood, v/e find that it preferves its brilliant
rednefs through all the channels which con-
vey it from the lungs through the heart,
and to the extremities of the body. But in
the other vefl^els, which receive it at the
extremities of the former, and convey it
through the heart as far as the lungs, the
blood is of a dark purple colour. The
former courfe is performed through the
pulmonary veins, the left auricle and left

ventricle

Factitious Airs. 79

Ventricle of the heart, the aorta and its
branches. The latter is performed through
the branches and trunks of the afcendine
and defcending cava, the right auricle and
right ventricle of the heart, and laftly,
through the pulmonary arteries, v/hich
convey it to the fpungy cells of the lungs,
where its colour is changed, &c.

The blood, therefore, having acquired
the oxygen in the lungs, conveys it as far
as the extremities of the branches of the
aorta, v^here the oxygen is depofited, and
the blood returns without it through the
veins.

It is difficult to fay under what form is
the oxygen combined with the blood, and
v/hat becomes of it at the extremities of
the arteries where it is left by the blood.
For want of dired: experimental informa-
tion concerning this interefting point, we
have only the light of analogy and con-
jedlure to lead us in the inveftigation of
truth.

In

8o Medicinal Properties of

In the combinations of the bafe of oxy-*
gen air with different bodies, fuch as tal^e
place in combuftions of every fort and de-
gree, three diiferent effects rnuil: be parti-
cularly remarked. The firfc is, that the
oxygenation is generally accompanied- with
colours of different intenfity ; the red being
produced more frequently than any other
colour, as is the cafe with mercurius calcl-
' natus per Je^ j-ed leady crocus martisy &c.
The fecond is, that by the acceflion of oxy-
gen a body is always rendered firmer or
more compad. Thus, by the com^buflion
of hydrogene and oxygen, water is pro-
duced, which is a much heavier and more
compadt fubflance than either of its two
components ; thus alfo by oxygenation oils
are thickened, and metallic bodies are con-
verted into a fubflance powdery indeed,
but whofe particles are firmer and harder
than the fame bodies in their metallic
ftate *. The third is, that a body lofes, in

great

* It is in confequence of the f^perio^ hardnefs of its
particles, that crocus martis (which is oxygenated iron)

and

Factitious Airs. 8r

great meafure, its capacity for containing
caloric, and of courfe gives out heat when-
ever it paiTes from a rare into a more covn-r
pad: ft ate of exiftence, and vice ver/a.
Thus water contains a great deal more of
caloric than ice, but much lefs than fteam f
hence when fteam is converted into water,
it depofits part of its caloric, viz. it com-
municates fenfible heat to the furrounding
bodies, &c,

Bv an eafy application of thofe facts to
the phsenomena of refpiration, we are led
to conclude, firft, that the rednefs which
the blood acquires in the lungs, indicates a
real oxygenation of that fluid ; fecondly,
that the oxygen is flightly attached to the
blood, for the blood eafily parts with it at
the extremities of the arteries ; thirdly, that
the oxygen, which is depoiited by the
blood at the extremities of the arteries, en-
ters into combination with, and gives firm-

and th^ oxyde of tin (commonly called />«//y)^ are .«m-
ployed for polifhing the hardeft fteel, glafs, and even
agates,

G nefs

82 Medicinal Properties of

nefs and folidity to, thofe particles of mat-
ter which give increment and liability to the
animal frame ; fourthly, and laftly, that as
the bond bf union between the blood and
the oxygen Is not very ftrong, and a^ tHc
union of the oxygen with other fubftances
at the extremities of the body' is rr>uch
llronger, therefore it feems evident that the
caloric of the oxygen air is not entii^ely
evolved from it in the lungs ; but that the
greater portion of caloric is evolved at the
extremities of the arteries, where the o5cy-
gen is more powerfully attra<fbed^' by' other
fubftances than it is by the blodd in tfce
lungs. Hence it follows, that the origin of
animal 1^ eat does not exift in tbe^ liir>gs
only, but that it takes place, more or lefs,
in every part of the body. And this^ ihevvs
why the whole body is nearly of the fame
temperature ; whereas, if the caloric were
evolved in the lungs only, that part of the
body would be much warmer than any
other, which is not tljX.^,Qafe

What

* I am happy to find that this explanation coiftcides
with the opinion of a verydillinguifhed and recent ana-
tomical

Factitious Airs, 83

What difpofes the blood to abforb the
oxygen in the lungs, and what forces it to
depofit that principle at the extremities of
the arteries, are queftions which the pre-
fent ftate of knowledge does not enable us
to anfwer fatisfaftorily. It has been fup-
pofed that the oxygen is attradied by the
ferruginous particles of the blood, and that
the rednefs of the blood is to be attributed
to the red colour of the oxydc of iron. But

lince

tomlcal writer, who exprefles himfelf in the following
words :

" But in refle£ling upon this moft difficult of all
fubjejSls, the generation of heat in the living body, many
things are to be taken in the calculation, which feem,
©n the flighteft glance, to be far more important than
this depofition of oxygene from the blood. It is a law
of nature, to which, as far as we know, no exception is
found, that a body, while it paiTcs from an aerial to a
fluid, or from a fluid to a folid form, gives out heat.
Now, what is the whole bufmefs of the living fyftem but
a continual aflimilation of new parts, making them con-
tinually pafs from a fluid into a folid form ? The whol^
nourifliment of the body goes on in the extreme vefl'el?,
and is a continual afTumption of new parts. The ex-
treme veflels are continually employed in forming fome
acids, which appear naked in the fecretions ; in forming

G 2 oxyds.

84 Medicinal Properties of

. iince it has been proved by a variety of ex-
periments, that the oxygen is attracted by,
and combines with, a variety of other fub-
ftances independant of iron or metals, I do
not fee the neceffity of attributing the at-
tradion of the oxygen to the ferruginous,
more than to other, ingredients of the blood.
Nor do I fee the abfolute neceffity of at-
tributing the red colour to the particles of
iron, fince other fubftances, in which iron
is not concerned, fuch as the oxydc of mer-

oxyds, as the fat and the jellies of the membranQUS and
white parts ; in the various depofitiojis of mufcle, bone,
tendon, &:c. for thefe are all continually abforbed, thrown
off by the urine, and inceflantly renewed. They arc
continually employed in filling all the interfaces of the
body with a bland fluid or halitus ; they are continually
employed in forming fecretions of various kinds. In
performing all this the power of the vefTels may do
much ; but the ultimate effect in each procefs muft be
a chemical change, and perpetual changes will produce
a conftant heat. Place the ors^an and focus of this ani-
rrial he3,t,-in the centre of the body, and you are embar-
rafTed in a'thoufand difficulties ; allow this heat to afife
in each part according to its degree of action, and each
part provides for itfelf.'* Bell's Anatomy, vol. II.

cury.

Factitious Airs. 85

cury, red lead, &c. owe their rednefs merely
to the oxygen which they have imbibed.

, It is difficult to account for the forma-
tion of the carbonic acid gas, and of the
watery vapour in the lungs ; for if thofc
fluids be really formed in that organ by the
combination of the carbone, and of the hy-
drogen, with the oxygene of the infpired
air j the whole, or nearly the whole, of the
oxygen air would be fo expended, and little
or none of it would remain to be imbibed
by the blood. The caloric like wife would
be employed in the formation of thofe fluids,
infliead of being difperfed through the body.
Is it not therefore more natural and more
fatisfadlory to fuppofe, that both the car-
bonic acid gas, and the water, are feparated
from the blood in the lungs, hut not formed
in that organ ? It is certain that carbonic
acid gas is introduced into the flomach by
the aliments ; and it is certain that the
chyle conveys it to the blood, why then
fhould we fuppofe that there is another for*
matiou of this gas. in the lungs ? As. for the
Q 3 watery

86 Medicinal Properties of

watery vapour, we may account for it in the
fame manner; and indeed the exudation of
water through the internal mennbranes of
the human body, is fo generally pradtifed
by nature for the purpofe of keeping thofe
membranes, &c. foft and pliant, that it
would be irregular not to admit the fame
exudation of water in the lungs alfo.

The expulfion ef putrid effluvia from the
body is confidered as another office of refpi-
ration. This is fhewn by the ofFenfive fmell
of the breath of certain perfons, who have
no bad teeth to account for it. But it is
difficult to afcertain in what cafes this may
take place, and how far it may extend.

It is with the appearance of probability
fuppofed that the oxygen, which the blood
depofits on the various parts of the body, is
partly expended in the exercife of mufcular
motion ; fince we find, that after unufual ex-
ertions of the body, a man breathes farfler,
and likewife takes in much more air at a
time, as if nature endeavoured by that

means

Factitious Airs. 87

means to recruit what has been lately ex-
pended in greater quantity than uluaL

The azotic gas, which is the greateft in-
gredient of common air, is conlidered as
only a diluent of the oxygen air, and as be-
ing otherwife paffive in the procefs of re-
fpiration. Yet this diluent anfwers a va-
riety of purpofes ; the principal of which
is, that it expofes a proper quantity of oxy-
gen air to a great quantity of blood, which
could npt have been the cafe if the atmo-
fpherical fluid had confifted entirely of
oxygen. This objedt is accomplifhed by
the very extenlive furface which the lungs
prefent to the air in its numerous cells ;
for the more numerous the cavities are, the
greater is the furface ; and, in faft, we find
that in thofe animals that are not much in
want of air, and that muft frequently fuf-
pend their refpiration for a confiderable
time, fuch as the fea-turtle and the frog,
the lungs qonfift of very few and very large
cells.

<3 4 The

88 Medicinal Properties cf

" The great proportion of azotic gas in
comiHon air, does alfo adapt that fluid to
the purpofes of vegetation, and other na-
tural procefles, the enumeration of which
is incompatible with the limits of this
E%.

CHAPTER VI.

A general Idea of the Application of aerial
Fluids for the Cure of D if orders incident
to the human Body.

J^ O N S T A N T obfervation has inform^
^^ ed mankind, from time immemorial,
that the air of certain places is more or lefs
falubrious than that of other places ♦ and
that the various qualities of the air in dif-
ferent fituations, are peculiarly favourable
to certain conflitutions. Phyficians, avail-
ing themfelves of this natural variety, have

long

Factitious Airs. 89

long been in the habit of lending their pa-
tients to fuch places as experience and ana-
logy indicated to be more favourable to their
refpiration. The fharp air of one place was
reckoned good for one diforder, the damp
air of a fecond place was efteemed ufeful in
other cafes, the pure air of a third was re-
commended in particular difeafes, and fo on.
Howfoever defeftive and erroneous their
knowledge of the real conftitution of the
atmofphere may have been, howfoever they
may have abufed the application, yet certain
it is, that the variety of effedls, fuitably to
the different qualities of the atmofpherical
fluid in different fituationsy is attefted by
innumerable fadls and univerfal obfervatlon.
Previoufly to the late difcoveries, the ideas
of phyficians refpe(fling the different qua-
lities and effeds of the atmofpherical fluid,
were vague, and generally erroneous. Ex-
perience, which ihewed them the advan-
tages that had been obtained in a number
of fimilar cafes, was their heft guide, and
all befides was doubt and obfcurity. The
prefent ftate of knowledge has, in great

meaiiire^

90 Medicinal Properties of

meafure, diffipated the clouds ; lince It has
not only ihewn the reafons upon which
certain qualities of the air depend, but has
likewife furnifhed us with the means of
procuring airs of oppofite qualities, and of
any degree of purity, at all times and
places, as alfo of applying them in all the
extenfive variety of quality^ degree of pu-,
rity, apd length oi time.

The apparatus necelTary for producing
the various feditious airs, may be eafily dcr
rived from the particulars that have been
mentioned towards the beginning of thi^
book \ but for a general apparatus, that ad-,
mits of cpmpadlnefs, cheapnefs, and a fuf-
ficiently extenfive application, I cannot re-
commend any better than, or nearly fq good
as, that which was contrived by Mr, James
Watt, engineer, of Birmingham; by means
of which the artificial airs, of fufficient pu-
rity, may be produced at a very moderate
expenfe, and eafier than by any other ge-
ueral method. Thofe apparatufes are now
made for fale, and a printed defcriptiQu,

with

Factitious Airs. 91

with neceffary praftical dire<fllons for the
ufe of its various parts, is given with each
apparatus, which fuperfedes the neceffity
of adding the fame to the prefent work. I
ihall, neverthelefs, referve, for the end of
the book, a Hft of the principal precautions
which ihould be attended to in the manage-
ment of Mr. Watt's, or of any other ap-
paratus of this fort, to which the pradti-
tioner may recur for extem.pore informa-
tion.

The artificial elaftic fluids are applied to
the lungs by the way of refpiration, to the
ftomach and inteftines, by means of injec-
tions, or in combination with fluids, and to
the external parts of the hodjy merely by
con tad.

Various apparatufes have been ufed for
the refpiration of faftitious airs. The leaft
exceptionable air-holder for this purpofe^
confifls of a large glafs receiver filled with
the required fort of elaftic fluid, inverted,
and fwimming in water ; out of which the
X air

92' Medicinal Properties of

air is refpired by means of a bent glafs tube,
which, paffing with its bent part through
the water, projeds one aperture above the
water within the receiver, whilft its other
extremity is apphed to the mouth of the
experimenter.

Instead of the above-mentioned bent
tube, the receiver may have an aperture
at its upper end, to which a tube is adapt-
ed, air tight, in an horizontal direction. Byt
as this apparatus requires a large tub full
of water for the receiver to fwim in, which
renders it rather cumberfome, and not very
portable, therefore other contrivances have
been fubftituted to the receivers. The ma-^
chine more in ufe for this purpofe, coniifls
of an oil-filk bag, furnifhed with a fhort;
wooden tube or faucet, which, when the
bag is full of the required aerial fluid, is
applied to the mouth of the patient. Thofe
bags are filled with the proper aerial fluid
by means of a glafs receiver, which, befid^s
its large aperture, has a fmall aperture with
a ftopple at the oppoiite end. The receiver

being

Factitious Airs. 93

being filled \¥ith the required air, and. in-
verted in water, the ftopple is removed from
its fmall aperture, and the wooden tube of
the bag is applied quickly to it ; then by
preffing the, receivers down into the water
of the tub, the air will be forced into the
bag. But with the air-holders, which form
.part of Mr. Wattes apparatus, the operation
is rather eafier, for which, fee the defcrip-
tion of the faid apparatus. The principal
imperfedion of thefe bags confifts in the
fmell of the oil-filk, which proves naufeous,
and almoft intolerable to delicate perfons ;
yet this fmell may, in fome meafure, be re-
moved *.

Instead

* For this purpofe Mr. Watt gives the foilowing
direfbions : — " To free oiled filk from its difagreeable
*' fmell, cut it into pieces of the fize wanted for the
** bags, and provide a fmboth table ' fomewhat larger
" than the pieces of filk, and a flat board of the fame
" fize as the table. Take charcoal frefli burnt in an
" open fire, untilit is free from fmoke, extinguifli it by
'' {hutting it up in a clean clofe vefiel, and reduce it to
*' powder. Sift this powder over the table to the
*' thicknefs of a quarter of an inch, or more, fpread a

*' piece

94 Medicinal Properties of

Instead of oil-filk bags large bladders
may be ufed % but as a bladder is not ca-
pable of holding a quantity of elaftic fluid
large enough for medicinal ufe, feveral ©f
them fhould be had in readinefs, each fur-

" piece of your filk upon it> and fift upon that again ano-
" ther layer of your charcoal dull, and thus proceed al-
" ternating the layers of filk, and charcoal, until the
<' whole of your filk is depofited ; then lay your move«
" able board upon the top of all, and leave the whole
*' undifturbed for four or five days. If, upon remov-
*^ ing the charcoal duft, the fillc has not ioft its Tmell en-
" tirely, repeat the procefs. The charcoal dull is to be
*' fwept ofF the filk, and the filk to be wafhed upon a
^ table with a wet fponge until it is clean. The bags
*^mufi: then be carefully fowed up, and the feams
'' anointed with japanner's gold fize, taking care to ufe
" that kind which does not become brittle when dry.
*' Green oiled filk fhould be avoided, as it is ftained by
^' means of verdigris, which rots its the yellowifh filk.
" is the beft.

** It is neceflary to obferve here, that although oiled
*' filk be the beft fubftance known for making the bags
*' of, it is very imperfectly air-tight ; and although
« charcoal-duft deprives it of fmell for the time, yet as
'' it can only attract the odoriferous particles from the
*' furface, it re-acquires fiame fmell by keeping, but by
" no means equal to what it had at firft."

niihed

Factitious Airs. 95

nKhed with a wooden or glafs tube, like the
oil-filk bags, through which they may be
filled, &c. ; fo that when the air of one
bladder is exhaufted, a fecond bladder may
be fubftituted, and fo on. Several bladders
might be ealily made to communicate with
each other, fo that through one tube or fau-
cet they might be filled all at once : four or
five large bladders thus joined together,
would contain about as much air as an ordi-
nary oil-filk bag, which is a quantity, in moft
cafes, fufficient for one application, and It
would laft about fix minutes. The bladders
have likewife an unpleafant fmell, which
may alfo, in great meafure, be removed '^.

Whether the glafs receiver, or the
oil-filk bags, or the bladders be ufed, the
patient mufl: always take care to keep his
noftrils accurately flopped whilft he draws

* For this purpofe turn the bladder infide out, wafh
it well with a weak folution of fait of tartar, then wafh
it feveral times over with fair water, fo as to remove
every particle of alkali ; laftiy, wafh it with fpirit of
wine,

the

96 Medicinal Properties of

the air into his lungs at every infpiration^
and to open them immediately after, fo as
to expel the air from his lungs through the
noftrils into the atmofphere at every expi-
ration, and not to return it into the bag or
receiver. This operation is not eafily per-
formed by moil perfons, and fome there are
who cannot perform it at all > in v/hich cafe
they breathe the fame air backwards and
forwards to and from the bag. But by this
means the air of the bag, even when lime-
water is contained in it, is contaminated lb
quickly as to do more harm than good.

This inconvenience, however, is com-
pletely obviated by the ufe of a little ma-
chine, which is to be interpofed between
the mouth of the patient and the faucet of
the bag. It confifts of a fmall box of wood,
having three apertures, to the two oppofite
of which two fhort tubes are faftened ; to
the third, which is a lateral one, there is an
external valve which will only permit the
air's going out of the box into the atmo-
fphere. One of thofe tubes is applied to

the

Factitious Airs. ^j

the faucet of the bag, and It contains a valve
which prevents the return of the air into
the bag ; the other tube is applied to the
mouth of the patient, who has nothing
more to do than to hold his noftrils con-
ftantly ftopped, and to breathe in a natural
way as long as there is any air in the bag or
receiver * ; it being eafy to underftand that
whenever he infpires, the air will pafs from
the bag into his lungs ^ but that at every
expiration, the air will be forced through
the lateral valve of the machine into the
ambient air.

Of the various forts of elaftic fluids, the
carbonic acid gas is the only one that has
been fuccefsfully applied to the ftomach or
inteftines, and for this purpofe it maybe
adminiftered two ways, 'dIz, either in the
aerial form in clyfters, or combined with
different fluids and given through the

* There are feveral perfons who, with very little at-
tention, can breathe through the mouth only ; when
this is the cafe, the keeping of the noftrils ftopped is fu-
perHuous.

H moiith.

98 Medicinal Properties of

mouth. For the former of thofe purpofds
the gas muft be firfl introduced into a blad-
der by the metliod already defcribed. For
the latter^ the gas is either naturally con-
tained in liquors, as in liewly fermented li-
quors, yeafl:, certain ripe fruits, and mineral
waters ; or is to be firft combined with the
required liquors, in which cafe water is the
fluid which is more generally ufed. This
impregnation of water and other liquors
with carbonic acid air, may be accomplilh-
ed by various methods, fach as by pouring
the liquor backwards and forwards from
one veffel to another, over the furface of
vegetable fubfiiances that are in a flrong
flate of fermentation \ or by filling a vefTel
partly with carbonic acid air, and partly
wdth the required liquor, and then fhaking
it for a minute or two, &c. But the bed
way of performing this impregnation, is by
means of a well-contrived machine, which
has been long in ufe, and is generally known
under the name of Dr. Nooth's glafs appa-
ratus, for making artilicial mineral waters.
There is, however, a contrivance for im-
pregnating

Factitious Airs. g^

pregnating water with an incomparably
greater quantity of carbonic acid gas, than
that which can be accompHihed in Dir.
Nooth's apparatus. But this contrivance i$
kept a fecret by the inventor, though the
water, fo highly impregnated by him, may
be had in London at a moderate price.

The application of faditious airs to the
external parts of the body, may be per-
formed with the utmoft facility. The aper-
ture of a tube, which proceeds ffom the
veffe] in which the gas is generated, may be
dlreded towards the part which is afFedted ;
a bladder full of the required gas may be
gradually preffed, fo as to throw a ftreani
of the gas upon it ; the part itfelf, as far as
it is pradlicable, may be introduced into a
veffel full of the required air ; or, laftly, a
fmall glafs funnel, with a bladder faftened
to its fmall end, and filled with the required
elaftic fluid, may be applied over the part,
with the edge of its large aperture clofe to
the fkin, fo as to prevent the efcape of the
gas into the circumambient air.

H 2 The

loo Medicinal Properties of

The medical application of faditlous
airs, and the effedts which have thereby-
been produced, are as yet labouring under
all the viciffitudes of truth and exaggeration,,
of accuracy and mifapplication, of iliort ex-
perience and uncertainty. The anxiety of
fome perfons, the ignorance of others, the
defire of fame, the love of intereft, and the
fear of dangerous innovations, have alter-
nately operated in favour and againft the
adminiftration of the elaftic fluids for the
alleviation of diforders incident to the hu-
man body. In the conflict of fuch oppofite
powers, it is difficult to feparate truth from
exaggeration and error ; it is impoffible to
afcertain the precife limits of their ufe and
efficacy.

Notwithstanding thofe weighty ob-
jections, I have endeavoured to colled:, to
examine, and to methodize all the ufeful
information which I could procure rela-
tively to the fubjeft, in hopes that a com-
prehenfive view of it might promote the
ufe, and in great meafure prevent the

abufe.

Factitious Airs. ioi

abufe, of a new clafs of remedies, which
have all the appearance of proving very ad-'
vantageous to mankind.

In tho^ ufe of oxygen air we have a lin-
gular flimulus, which admits of its being
rendered more or lefs adiive by dilution
with various proportions of common air.
In its pure, or nearly pure, ftate, it is a
powerful exciter of fufpended animation ;
and when diluted with a coniiderable
quantity of common air, it is a gentle
ftimulus, which, by invigorating the various
parts of the animal body, by communica-
ting firmnefs to the folids, and energy to
the fluids, does frequently obliterate the
caufes of morbid habits.

The ufe of azotic gas^, and of the vari-
ous fpecies of hydrogen gas, produces a
diminution of the irritability of the animal
fibre to any degree, and hence it becomes
ufeful in a variety of thofe diforders, which
depend on an increafed irritability, fuch as
inflammations, coughs, fpafms^ &c.

H 3 In

102 Medicinal Properties of

In the ufe of the carbonic acid gas wc
have a powerful antifeptic, and in certain
cafes a folvent of confiderable efficacy.

The ufe of pure oxygen air is confined
to the purpofe of exciting the dormant
powers of fufpended animation, and it is,
therefore, to be adminiftered to children
born apparently dead, or overlaid ; to per-
fons fuiFocated by drowning, by fteam of
charcoal, by foul air, &c. whenever the
circumftances of the cafe may indicate a
poffibility of recovery.

Those cafes excepted, the refpiration of
pure, or nearly pure, oxygen air, is almoft
always attended with unfavourable fymp-
toms, fuch as a preternatural heat, efpeci-
ally about the region of the lungs ; a
quickened and feverifli pulfaticn , inflame
mation, &c. And thofe fymptoms come orf
after a ihorter or longer ufe of the oxygen
air, according to the particular conftitution
of the experimenter, and the purity of the
gas.

But

Factitious Airs. 103

But when the oxygen is diluted with
much common air, viz, in the proportion
of one to eight, and even as far as one to
twcntjy it then is a fafe and very ufeful
remedy, whofe principal adtion confifts in
giving tone, elafticity, and confiftence to
the fluid as well as to the folid parts of the
body, and of courfe it promotes all the na-
tural confequences of thoft effefts, viz. it
quickens languid circulation, it ftrengthens
the organs of digeftion, promotes fecretion%
invigorates debilitated habits, and it aflifts
nature in throwing off bad humours, and
other lurking caufes of difeafes.

It has been obferved, that fome indivi-
duals can bear a much greater proportion
of oxygen than others, which is analogous
to the various difpoiitions for all other ap-
plications. Thus a certain quantity of any
remedy will ad; powerfully on fome per-
fons, whilft it will not be even felt by
others. Thus alfo a certain quantity of food
produces ilrength and cheerfulnefs in fome
individuals, whilfl it produces iicknefs and
H 4 indigeftion

104 Medicinal Properties of

indigeftion in others. It therefore becomes
neceffary, in the application of this remedy,
to regulate the proportion of the two elaftic
fluids agreeably to the conftitution of the
patient, which may be eafily accompliflied
by means of a very few trials.

In the diluted ftate, the oxygen air is ad-
miniflered by letting the patient breathe it
for five or ten minutes once or twice a day.
It might probably prove more efficacious, if
it were breathed in a more diluted ftate for
a longer time ^ but the preceding mode has
undoubtedly been attended writh falutary
effedls.

However flight this application may
appear, however fmall the unufual quantity
of oxygen which is thus introduced may
be, the effects have been proved and con-
firmed by a variety of experiments and me-
dical cafes. But independent of the expe-
rimental proof, the improbability of the
efl'ed: will difappear if it be confidered, that
the lungs of moft perfons, and efpecially of
thofe who labour under certain difeafes,
4. are

Factitious Airs. 105

are almoft immediately relieved or afFedted
by the tranlition from the air of one place
to that of another ; as by their going oul;
of town, or even out of the houfe; and
yet, as has been already obferved, the dif-
ference between the air of a town and the
air of the country, or of that of a houfe
and of the external air, is fo very trifling
as hardly ever to be diftinguilhed by the eu-
diometer. Extremely minute, and almofl in-
conceivably fmall, quantities of matter caa
ad with wonderful efficacy, when they are
introduced into the circulation of the blood.
The inoculation of the fmall-pox, and the
experiments with poifons, furniih fuffi-
cient confirmation of this obfervation*

By breathing a mixture of common and
oxygen air, even when the latter does not
exceed one-eighth part of the former, for
about ten or fifteen minutes, the pulfe Is
generally quickened of a fev^ ftrokes, but it
is almoft always made ftronger. The lungs,
during the operation, are feldom fenfibly^
afleded -, but on leaving off the mixed airs,

and

io6 Medicinal Properties of
and returning to the atmofpherical air, a
degree of tightnefs is frequently felt on the
cheft, which, however, gradually goes off
and vaniflies after a few minutes time*

When debilitated habits breathe the di-
luted oxygen air for about a quarter of an
hour once or twice a day, the improvement
of their health is hardly ever confpicuous
in lefs time than a week or a fortnight;
but after that period, they will find their
ftrength, their appetite, their digeftion,
their circulation, and other fundlions^ itn-
fibly improved ; and this improvement goes
on progreffively to a greater or lefs degree,
according as age, local indifpofitions, times
of the year, and other circumftances may
allow.

The mixtures of common air with azo-
tic gas, or of common air and any fpecies
of hydrogen gas, are commonly denomi-
nated reduced atmojpheres ; for, in fad:, they
contain a fmaller quantity of refpirable
fluid, than is contained in an equal quantity

of

Factitious Airs. 107

of common air. The principal efFeft of
thofe reduced atmofpheres, is to diminifh
the irritability of the parts fubfervient to
refpiration, and indeed of the whole bodv ;
for which reafon they are fuccefsfally ad-
miniftered in inflammations of the lano-s,
in fpafmodic coughs, and in all the difor-
ders that are nearly allied to thofe.

Much caution mufl be ufed in the ad-
miniftration of thofe reduced atmofpheres,
as fome of them are produdive of alarmino-
fymptoms. The mixture of azotic and
common air, in which the former fhould
never be more than a quarter of the latter,
is the leaft dangerous, and at the fame
time the leaft efficacious. The fame thing
m.ay be faid of the mixture of common air
with the mild fort of hydrogen gas, viz^
that which is produced from iron and di-
luted vitriolic acid, or by paffing the fteam
of water over red hot iron, excepting that
it is rather more efficacious than the pre-
ceding. But the hydrocarbonate is much
more powerful and more dangerous than
\ . any

io8 Medicinal Properties of

any of the abovementioned gaftes, efpecially
when frefli made. It fhould, in general, be
mixed with about twenty or thirty times
its bulk of com.mon air, unlefs fome par-
ticular cafe may feem to require a greater
proportion of the dangerous gas. For moil
purpofes it will fuffice to breathe it for
about five minutes a day.

The breathing of the diluted hydrocar-
bonate is attended with a diminution of
fenfibihty, efpecially about the cheft, and
this effeft is frequently fo great, that fome
perfons have expreffed it by faying, that
they felt as if they had no lungs at all, even
when they had been a few minutes before
in excruciating pains. But this diminution
of fenfibility is almoft always accompanied
with vertigo or giddinefs, with a lowering
of the pulfe, and with faintnefs. It muft be
particularly remarked, that though thofe
fymptoms in general come on imm.ediately
after the operation, yet fometimes they
return once, and even twice, more in the
courfe of the day. When the breathing of

reducecj'

Factitious Airs. 109

reduced atmofpheres proves very trouble-
fome, it may be interrupted for a fevy
minutes.

Its great power in checking irritability
and fenfibility, feems to render the diluted
hydrocarbonate applicable to fome difor-
ders that have hitherto eluded all medical
application j and as one of the moft likely
to be relieved by this treatment, I ihall
mention the hydrophobia, or madnefs which
is occafioned by the bite of mad dogs, or
other mad animals *.

A REDUCED atmofphere, capable of di-
miniChing in fome degree the irritation of
the lungs in inflammations, coughs, and

* I have been told, and have read, though I cannot
at prefent recollect virhere, that the ufe of opium, and
likev/ife that the fufpenfion of animation for a time by
accidental drowning, have adually cured the hydropho-
bia in two or three cafes. If this be true, the probabi-
lity of the hydrocarbonate proving beneficial, is thereby
much increafed.

c^rtaia

no Medicinal Properties of

certain fpecles of afthma, has been expedi-^
tioufly formed by mixing the vapour of
vitriolic ether v^ith common air. For this
purpofe the patient needs only hold a fmall
phial of ether open near his mouth, for
about an hour at a time or longer, by
which means the vapour of the ether mixes
with the air that enters the lungs in the
ufual Qoxxri^ of refpiration, and converts it
into an inflammable, or rather an explolive,
aerial fluid *. For this purpofe it has been
found ufeful to mix fome powdered leaves
of hemloc (ciciita) with the ether. The
ether [viz. about a quarter of an ounce of
it) may alfo be put in a common tea-pot, and
the mouth may be applied to the fpout of
it, fo as to draw the air through it, and
through the vapour of the ether.

The carbonic acid gas has been longer
in ufe as a medicine than any other fadl-

* If three or four drops of ether be fhook In a phial
full of common air, and if afterwards the aperture of the
phial be prefented to the flame of a candle, the air In it
will explode like a mixt«re of common air and hydrogen
gas.

tious

Factitious Airs. m

tious aerial fluid. Much has been done,
and much has been written, relatively to it.
But the ufeful refult of thofe experiments
and inveftigations will be found condenfed
in the following few paragraphs.

Im putrid fevers the free ufe of carbonic
acid gas has been of confiderable ufe, when-
ever the urgency of the cafe has not been
very great, viz, when time was allow^ed for
the gas to operate upon the morbid matter;
and when the diftention of the bowels was
not fo great as to prevent th€ free ufe of
the gas.

In the fcurvy this gas has been of con-
fiderable ufe in the beginning of the dif-
order, rather more than in an advanced
flate of it. But the ufe of vegetables, of
fugar, and of other fubftances that contain
it in great abundance, are acknowledged to
be ufeful in all ftates of that diforder. Ex-
perience likewife inform us, that in the ufe of
carbonic acid gas we are not to exped: an
unlimited antifeptic, nor a perfed: folvent of

the

112 Medicinal Properties of

the ftone in die urinary bladder ; yet its ufe
in putrid cafes, and in fome difeafes of the
bladder or kidnies, is attended with confi-
derable benefit.

The external application of carbonic
acid gas to fores and ulcers of every fort, is
unq^ueflionably very ufeful.

Af t e r a careful coniideration of the pre-
ceding general and compreheniive profped:
of the medicinal ufe and efficacy of the
aerial fluids, we may eafily regulate the
meafure of our hopes by the ftandard of
reafon and experience. The idea of finding
in them a remedy, capable of curing con-
fumptions in all their ftages, muft be laid
afide ; and the hope of healing all forts of
internal ulcers will naturally vanifli. The
ufe of reduced atmofpheres does undoubt-
edly diminifli the irritability of the fibre,
and a diminution, of irritability favours the
healing of certain ulcers, but by no means
of them all ; nay, in fome cafes it will even
produce the contrary eftedl. The'^ufe of

oxygen

FACtlTIOUS AlR^. 113

oxygen air has been found advantageous in
many of thofe diforders that are called ner-
vous, and it has undoubtedly ftrengthened
and invigorated feveral debilitated or ema-
ciated habits -J but it vv^ould be abfurd to
exped; that it fhould prove beneficial in all
cafes of emaciation and debility, fince thofe
vifible effecSs are often produced by caufes
that may be rather fomented than checked
by the ufe of oxygen air*

In moft of the diforders incident to the
human body, the various concurring cir-
cumfiances are far from being known to
their full extent ; hence theory may fuggeft,
but experience muft prove the ufe of cer-
tain pradlices. Improvements and difco-
veries may be generally urged and ex*
pefted ; but where theory and experience
are iilent, we have no warrantable guide to
affift us in the inveftigation of new pro-
perties and new applications*

114 Medicinal Properties of

CHAPTER VIL

Of the f articular Adminijlration of aerial
Fluids in different Diforders.

AFTER a general idea of the applica-
tion of factitious airs by way of re-
medies tc the human body, it will be ne-
ceflary to flate thofe modes of treatment,
which experience or analogy fhew to be
the moll efficacious in particular difeafes.
But this ftatement cannot be attended
either with great accuracy of defcription,
or with extenfive information concerning
the phasnomena, that are really produced
by the fadlitious airs in all cafes. The vari-
ous nature of individuals, the imperfedt ac-
counts of feveral cafes, and the frequent ad-
miniftration of other medicines in conjunc-
tion with the . aerial fluids, limit for the
prefent the attainment of the abovemen-
tioned objedls*

All

FagtitIous Airs. ii|

All that the pra6litioner may expeft to
derive from the prefent chapter is> a guidd
or indication for the commencement of the
apphcation, a general view of the principal
effedls that are produced by the particular
adminiftrations, and a warning againft mif-
takes. But with refped to the continua-
tion, or fufpenfioni or alteratioUi of the
treatment, he can only be inftrufted by a
careful obfervation of the phasnomena which
take place in the courfe of the applica-
tion.

1 SHALL forbear mentioning other me-
dicines that may be proper to be admini-
ftered at the fame time with the gaffes, as
thefe muft be left to the judgment of pro-
feffional gentlemen. But I would ftrongly
recommend to adminifter them as fparingjy
as the nature of the cafe can poffibly admil
of; being perfuaded^ that the good effects
of the aerial fluids is frequently counter-
afted by the adtion of other medicines.

N. B. The difeafes iii the following
pages are arranged in alphabetical order.

I 2 Animation

ii6 Medicinal Properties of

Animation Jufpended.

IN cafes of this fort, whether they be
oceafioned by drowning, by noxious va-
pours, or by any other caufe of the like na-
ture, the oxygen air fhould be adminiftered
pure, or nearly fo. The wooden pipe of a
large bladder full of it muft be introduced
into the mouth of the fubjed:, the lips muft
be prefled upon the faid pipe, and the nof-
trils muft be flopped by the hands of an
afliftant. Then by preffing the bladder, the
oxygen air muft be forced into the lungs, as
much as poffible, for about eight or ten
feconds, after which the mouth and noftrils
being unftopped, without removing th^
pipe of the bladder, the cheft about the
region of the lungs muft be prefted gently ;
then the bladder being applied as before,
the oxygen air is forced again into the
lungs, and fo on j continuing a fort of
forced and artificial refpiration for about a
quarter of an hour at leaft, if no figns of

life

Factitious Airs. 117

life appear before that time *. But as foon
as any natural or fpontaneous movements
are perceived, the preffing of the region of
the lungs may be difcontinued, and the
bladder, &c. muft be removed ; for in that
ftate a free ventilation of the ambient air
will be found fufficient to reftore life.

This treatment fhould be accompanied
with the communication of a gen tie warmth,
and perhaps with frid:ion to the hands and
feet. But care muft be taken to do what i^
juftnecefTary, and not too much; for in the
attempts to reftore animation, the ftimuli
and other applications are frequently carried
fo far, as to deftroy that laft fpark of life,
which they were intended to revive.

In cafes of children born apparently
dead, or ftrangled in laborious parturition,
&c. the ufe of oxygen air cannot be too
forcibly recommended. The application is
eafy and highly promifing. Independent of

* Several bladders full of oxygen air fhould be kept
imeadinefsj for a fingle bladder v/ill be foon exhaufted.

I 7 the

ii8 Medicinal Properties of

the experiments that have been made on
brutes, I know of a cafe, in which a child
born apparently dead, was brought to life
merely by forcing oxygen air into his lungsj
whilfl; he was held before the fire,

Jijlhma,

I FIND many creditable accounts of
this diforder having been relieved, and
fometimes perfedly cured, by the ufe of
diluted oxygen air in fome cafes, and by the
ufe of reduced atmofpheres and the vapour
of ether in other c^fes.

It would be abfurd to imagine, that
either of thofe treatments may be indif-
criminately applied to the very fame fpecies
of afthma; but the diftindtions are not
clearly ftated in all the accounts of the cafes.
It appears, however, that in a plethoric
afthma, and when the diforder is attended
with confiderable pain, hard cough, and in-
flammatory fymptoms, the reduced atmo*
fpheres muft be adminiftered.

Factitious Airs. 119

In thofe cafes the patient may be di-
redled to breathe daily fixteen quarts of
common air, with four quarts of hydrogen,
obtained from iron and diluted vitriolic
acid, or, which is better, from the vapour
of water and red-hot iron. But fhould this
mixture of elaftic fluids prove ineffedlual in
a day or two, then a mixture of one pint of
hydrocarbonate and thirty pints of common
air, may be ufed inftead of it 5 and the
ftrength of this mixture may be increafed
according to circumftances. If in breath-
ing the diluted hydrocarbonate, giddinefs
fhould come on, the patient muft be
defired to intermit the operation 5 refling,
that is breathing the ambient air, for a
few minutes, and then to refume the in-
halation of the diluted hydrocarbonate.
Thus the operation may be intermitted
three or four times.

The breathing of the vapour of ether,
after the manner defcribed in the preceding
chapter, has been found to afford confidera-
ble alleviation of the pain and oppreflion in
thofe cafes.

I 4 In

120 Medicinai, Properties of •

In nervous afthrna, and efpecially in de-f
bilitated habits, the oxygen ^ir may be ad-
miniftered ; and it will be proper to begiri
by inhaling daily eight qua|-ts pf commonj^
with two quarts of oxygen, air, extracted
from manganefe by means of heat. The
quantity of oxygen may be increafed, in cafe
the abovementioned proportion fhould be
found ineffedual j and it is remarkablcj^
that in this fpecies of difeafe the patients
can fometimes bear a great quantity of oxy-
gen without any material eiFe(ft.

In all cafes of afthma, the efFeds of the
application of fadlitious airs piay be per-
ceived in the courfe of four or five days j
but thq accomplifliment of the cure will
frequently require fix weeks time, or longer*,

Cancer.

THE ftubborh nature pf a cancer, and
its dreadful confequences, render every hint,
that promifes an alleviation of its efFed:S;|
extremely interefting.

The

' , Factitious Airs. isi

The jelaftic fluids have been repeatedly
applied to cafes of this fort, and fuch ap-
plications hav.e been attended with confi-
derable advantage, 1 do not find any au^
thentic account of a cancer having been
completely cured by the ufe of faditious
airs. But certain it is, that in a variety of
cafes the pain has been confiderably dimi-
nifhed, the fcetor as well as the bad afpeft
of the ulcer, have been almoft entirely re-
moved, and the whole habit of body has
been confiderably improved, fo that the pa-
tients have thereby been enabled to have
comfortable nights, more cheerful counte-
napces, &c,

Those good effeds have been produced
by the external application of carbonic acid
gas to the ulcer, and the inhalation of di-
luted oxygen air. Both thofe elaftic fluids
mufl: be adminifl:ered daily for weeks, or as
long as the indications of the cafe may
afford a hope of melioration. The manner
of applying the carbonic acid gas has been

already

122 Medicinal Properties of

already defcribed * ; as for the continuance
of the application, an hour a day is by no
means too much, and it would be better if
fuch an application were repeated two or
three times in the courfe of each day. With
refped: to the oxygen, two or at moft three
quarts of it, with about fourteen or (ixteen
quarts^ of common air, may be fufficient fc«r
each daily inhalation*

Catarrh.

Im colds and de fluxions, efpecially when
accompanied with tightnefs about the re-
gion of the lungs, and a hard cough, much
and almoft inftantaneous relief has been
frequently obtained by breathing a mixture
of about four quarts of hydrogen and twenty
quarts of common air^ There is no need of
breathing this quantity at once. It will
hardly ever be neceffary to repeat this ap-
plication longer than the third day. The
breathing of the vapour of ether in the

* See chap. VI. p. 99.

manner

Factitious Airs. 123

manner already defcribed, wiU anfwer nearly
as well as the above-mentioned mixture of
elaftic fluids, and it has the advantage of
being a much eafier application, lince it re-
quires no particular apparatus *•

Chlorojis.

THE adminiflration of diluted oxygen
lair has proved beneficial in difeafes of this
kind, perhaps more often than in any other
diforder, as is proved beyond a doubt by
feveral authentic cafes. The palenefs, the
debility, the palpitation, the fever, the de-
praved appetite, a^nd the other bad fymp-
toms which accompany this diforder, ge-
nerally begin to diminifh in about four or
five days, and a complete cure is often ac^
complilhed in about fix weeks time.

The daily inhalation of one quart of oxy-
gen, and ten or twelve quarts of common,
air, may fuffice for the beginning. But it

* See chap. VL p. jio.

is

124 Medicinal Properties of

is to be remarked, that chlorotic patients
are ienfible of the lead excefs in the propor-
tion of oxygen, fo that fometinies they are
more hurt than benefited by it, unlefs fuch
a quantity of it be adminiftered as may
be juft neceffary; and this quantity can
be iliewn only by a careful obfervation of
the eiFed:s which take place. The lungs
will be enabled to bear the ftimulus of oxy-
g(^n air ev^ry day better and better,

Confumpthn,

THE various ftates of confumption, or
phthijis pulmonarisy its different caufes, and
the difficulty of difcerning a real phthifis
from certain other dlforders, render the
treatment of this difeafe frequently doubtful
and perplexing. But its ftubborn nature,
and the frequency of the difeafe, demand
the utmofl attention, and all the affi fiance
which philofophy can fuggeft, and the me-
dical art can apply. We fhall therefore en-
deavour to flate, how far the ufe of fadli-
tious airs has been found ufefulor promifing
in cafes of this nature.

3 ^^

Factitious Airs. 125

It has been faid on one fide, that the
faditious airs have the power of arrefting
the progrefsof confumption,and often of ac-
compUfhing a perfect cure; but on the other
hand it has been afferted, that they have
never afforded any permanent benefit, and
that they have often produced manifeft harm.
It appears, however, from a dinnterefted
examination of the cafes, and from the tefti-
mony of patients as well as of praditioners,
that both thofe affertions imply a confider-
able degree of exaggeration. The refult of
this examination will be found condenfed in
the following paragraphs*

' The diluted hydrocarbonate is the only
one, or at leaft the principal aerial fluid
that has been fuccefsfully adminiftered in
cafes of phthifis ; and it has generally af-
forded a fenfible and almoft immediate re-*
lief, by abating the hedic fever, by dimi-
niihing fenfibility, by promoting fleep, and
by reducing the quantity of expeftoration.

But the ufc of hydrocarbonate is always
attended with a diminution of ftrength.

Hcnce^.

126 Medicinal Properties of

Hence, when the patients are very feeble>
which is generally the cafe in an advanced
ftate of the diforder, the difadvantage which
arifes from the diminution of ftrength, is
greater than the advantage which arifes
from the other good eiFe6ls of the hydro-
carbonate. When the patients, therefore,
are too far gone, the ufe of the hydrocar-
bpnate produces an apparent but not a real
melioration.

It is on the fame account that this elaf^
tic. fluid cannot be adminiftered to patient^^
that labour under great weaknefs of the di-*
geftive organs. In fuch cafes the vapour of
ether is, perhaps, the only elaflic fluid that
may be tried with fafety ; and the ufe of it
is attended with at leafl a temporary re*
lief.

There are two or three cafes of real
phthilis creditably related, v/here a perfed:
cure feems to have been performed ; though
in a great many others the application of
aerial fluids proved evidently ufelefs. But

though

Factitious Airs* 127

though from thofe few fuccefsfal cafes no
great expedlations can be derived, yet in a
difeafe where no remedy has ever been found
efficacious, furely it is not improper to try
an appHcation which at leaft affords a ray
of hope.

The quantity of diluted hydrocarbonate,
which may be adminiftered daily, is various,
according to the conflitution of the patient.
It is proper, hovv^ever, to begin by admi-
niilering one pint of hydrocarbonate with
between twenty and thirty pints of common
air ; and the quantity of the former may,
in procefs of time, be increafed conformably
to the efFedts. In breathing this quantity
of elaftic fluid, it will be proper to let the
patient reft four or five times, or in fliort
whenever any giddinefs happens to come
on ; for this giddinefs or vertigo generally
goes off in two or three minutes, after which
the patient may again apply his mouth to
the bag or vefTel which contains the diluted
hydrocarbonate.

I^

128 Medlcinal Properties of

It will be found, that cuflom habituated
the lungs to bear the hydrocarbonate, in an
increafed proportion, as far as a certain limit*
Thus the fame patient who at firft was
made vertiginous by a quart of hydrocar-
bonate, diluted with twenty quarts of com-
mon air, will, in procefs of time, be hardly
afFedted by the double of that quantity*

The inhalation of the vapour of ether, as
alfo of other forts of reduced atmofpheres>
fuch as a mixture of azote and common
air, of carbonic acid gas and common air, of
hydrogen and common air, have been of
partial ufe; however, the mixttare laft-men--
tioned feems to have proved more beneficial
than any of the reft. This fort of reduced
atmofphere muft be adminiflered more freely
than the diluted hydrocarbonate. The va-^
pour of ether may be inhaled with the ut-^
moft facility, as no apparatus is required
for it, and it will be found at leaft of tem-
porary ufe for allaying the cough, the pain,
&c-

Though

f'ACTiTious Airs* 129

TiiouGH the ufe of reduced atmofpheres
be more promifing in cafes of incipient
phthifis, yet that application fhculd not be
neglected in any ftate of the diforder ; fince
the elaftic fluids are the only remedies which
can be applied immediately to the part af-*
fedted*

Of the various fpecies of phthifis pulmo-
naris, tv/o only, viz, the chlorotic and the
fyphilitic, feem to require a different treat-
ment, and I find a few cafes in which fy-
philitic ulcers in the lungs are faid to have
been cured by the ufe of diluted oxygen,
which was breathed once a day 5 but this
treatment was accompanied with mercurial
and other medicines; which, however, when
adminiftered by themfelves, had produced
no good efFefl:,

The inhalation of carbonic acid gas is
faid to have proved beneficial in hedic dif-
orders, but I do not know how far this prac-
tice may be iafe or ufeful, as I do not find
any very particular information concern-
ing it.

K Coughs

130 Medicinal Properties of

Coughs^

6F the various fpecies of cough, thofe
which originate from catarrh and from
phthifis have been already mentioned under
thofe articles^ to which the reader is re-
ferred. But with refpecl to the appUcation
of faditious airs to other fpecies of cough,
I do not find much authentic information,
and of courfe muft leave it for future in-
veftigation.

AN univerfal debility is not unfrequently
met with amongft perfons of all ages, and
efpecially among women. It is fometimes
the unconquerable effedl of former diforders
that are fubdued, or of lurking and invifible
caufes. Whatever its origin may be, the
fymptonvs it produces are numerous and
often of the utmofl confequence. It pro-
duces palenefs, emaciation,, difficulty of
breathing, palpitation, indigeflion, lofs of
fleep, frequent cough, fwellings of the ex-
tremities.

Factitious Airs. I31

tremities, weaknefs of fight, lofs of" voice,
fuppreffion of the ufual evacuations, &c.
Thofe fymptoms, of which a greater or lefs
number is to be obferved in the fame indi-
vidual, are, at firli, the confequence of the
debihty, but they foon become the fo-
fhenters of that very languor, and confe-
quently of each other.

When the difeafe, which produces the
languor,' is prefent and known, I need hardly
mention that the removal of that caufe
ihould be the iirft objedt of thepradtitioner.
But when that is not the cafe, diluted oxy-
gen air may be adminiftered with great
hopes of fuccefs ; for fuch treatment has
been found beneficial in a great many cafes
of this fort, and wonderful cures have been
performed where no other remedy was
found efficacious. The improvement is
perceived fooner or later, according to the
nature of the cafes ; but, generally fpeaking,
it becomes manifeft in about a fortnight or
three weeks time. It operates by ftrengthen-
ing and improving the whole habit. The

K 2 pulfe

132 Medicinal Properties of
pulfe becomes ftronger, the afpedt acquires
colour, the laffitude after exercife goes oiF
gradually, the appetite is improved, and the
reft of the fymptoms difappear gradually.

It has been repeatedly obfervcd, that in
cafes of this fort the quantity of oxygen
muft be nicely regulated by the ftrength of
the patient. If too fmall a quantity be ad-
miniftered, little or no improvement will be
obtained 5 but if the quantity be too great,
the effeds will be hurtful, and fome of the
bad fymptoms are thereby increafed. A
few days experience v^ill foon indicate the
proper dofe of oxygen. But I would re-
commxnd to begin by giving one quart of
oxygen, with twelve or fifteen quarts of
common, air, per day, and to increafe or
diminiih the quantity according to circum-
ftances. It muft, however, be remembered,
that when a fenfible improvement becomes
manifeft, more advantage is to be derived
from a moderate dofe regularly adminiftered,
than from an increafed proportion of oxy-
gen.

I DO

Factitious Airs. 133

I DO not find that the leaving off of this
application has ever been productive of any
harm, but at all events it may be not im-
proper to relinquifli it by degrees, i;/^;. by
diminifhing the quantity of oxygen, and in-
termitting the application by the interval of
a day or two.

Digejiion impaired^ or Dyfpepjia.

WE have not a clear account of the
various fpecies of dyfpepfia to which the
aerial fluids have been applied, nor indeed
have they been tried in a great variety of
cafes. But upon the whole it appears, that
when debility is the caufe, and efpecially
when it is accompanied with what is called
a nervous head-ach, the inhalation of di-
luted oxygen air has been of Angular ufe,
and the diforder has been frequently re-
moved in a {hort time.

If the impaired digeftion be accompa-
nied with other iymptoms of debility be-
fides the head-ach, the adminiilration of

K 3 oxygen

134 Medicinal Properties of
oxygen may be regulated agreeably to what
has been mentioned in the preceding ar-
ticle, otherwife a greater proportion of it
may be adminiftered, as about four or five,
or fix pints of it, with between twenty and
thirty of common air. In cafes of this fort,
the good efFed:3 of the oxygen may be per-
ceived in the courfe of a few days.

This treatment has proved peculiarly
beneficial to fuch perfons as have con-
trafted a weaknefs of digeftion, from having
been confined in the foul air of workfliops^
counting-houfes, &c,

I FIND, likewife, the cafe of a man wha
had been afflifted for upwards of five years
with heart-burn, flatulence, lovvnefs offpi-
rits, and coldnefs of the extremities, which
feemed to indicate a bad digeftion, and who
was perfed:ly cured by the inhalation of di-
luted oxygen, and by drinking water im-
pregnated with carbonic acid gas, together
with fome fait of ftcel.

Dropjy.

Factitious Airs. 135

Bropfy.

IN a variety of dropiical cafes the inha-
lation of diluted oxygen air has been at-
tended with fuccefs, and this fuccefs has
feveral times amounted to a complete cure.
This treatment feems to be more efficacious
in an incipient dropfy, and when the dif-
order is confined to the extremities, than
in other ilates of it. Yet I find a re-
markable cafe of hydrothorax which was
efFed:ually cured, though a fimilar one was
not attended with the fame effed; and like-
wife a cafe of water in the head of a boy of
thirteen years, which is faid to have been
partially removed by the inhalation of. di-
luted oxygen air.

One quart of oxygen, and about fifteen
of common air, per day, may be fufficient
for the beginning j but the proportion of
oxygen mull be increafed in the courfe of
three or four days (provided no bad effedts
enfue) to two quarts ; and foon after it will

K 4 be

J36 Medicinal Properties of

be proper to double the quantity both of
oxygen and of common air.

This regimen muft be perfifted in for
weeks and months, according to the nature
bf the cafe j and ihould any inflammatory
fymptoms appear in the courfe of this ap-
plication, the inhalation of the diluted oxy-
gen may, in that cafe, be fufpended or mo-
derated for two or three days.

'Eruptions,

I FIND a few cafes of fcorbutic erup-
tions on the face, as alfo on other parts of
the body, in which a complete cure was
accompliihed by the daily inhalation of di-
luted oxygen air.

In cafes of tumors and eruptions, which
derive their origin from debility and a poor
or thin ftate of the blood, the like treatment
has been found beneficial.'

Two

Factitious Airs. 1-^7

Two or three pints of oxygen, with
about ten times that quantity of common
air, per day, is fufficient for the beginning ;
but in cafes of this fort, the proportion of
oxygen fhould not be much increafed.

I NEED hardly add, that in fuch cafes it
is proper to continue the ufual dreffings of
the parts affedled, the means of keeping the
body gently open, &c.

Fevers,

I DO not know whether the faftitious
airs have been tried with fuccefs in other
forts of fever, befides the putrid and the
hedic. With refpecl to the latter, the
reader may confult v/hat has already been
faid under the articles of chlorojis and con^
fumption. But in putrid fevers the carbonic
acid gas is generally allov/ed to be an ufeful
remedy ; yet the ufe of it has not proved
fo generally beneficial as it was at firft be-
lieved.

This

138 Medicinal Properties of

This gas is applied internally, not to the
lungs but to the ftomach and inteftines, in
three different manners, viz. by way of
clyfters, either in the aerial form or in com-
bination with water; by way of drink when
combined with water ; and, laftly, by giving
through the mouth fuch fubftances as con-
tain carbonic acid gas in abundance, that is
liquors in a ftate of fermentation, certain
fruits^ &c.

When a large quantity of it is giverr
either in the aerial form or in combination
with water, the abdomen is frequently dif-
tended by it ; for though this gas is pretty
eafily imbibed by animal fluids, the fluids
which It ufually meets with in the ftomach,
tsiQ. are feldom capable of abforbing more
than a moderate quantity of it. However,
the diftention of the abdomen is not fo very
detrimental, but it may be fupported to a
certain degree.

What feems to render the carbonic acid
gas not fo efficacious in cafes of putrid

fevers.

Factitious Ams, 139

fevers, as from its ufual properties one
might be led to expert, is the difficulty of
its infinuation into the vafcular fyftem of
the whole body. The lafteals imbibe it in
fmall quantity, and the difficulty becomes
greater in certain ftates of the diforder;
whenever, therefore, the difeafe is not in a
very alarming ftate, viz. fo as to give time
for the infinuation of the carbonic acid gas
into the fluids of the body, then more
benefit is to be expefted from it. There
are, however, fome cafes in record, where
the free ufe of carbonic acid gas proved
efficacious in the worft ftate of putrid dif-
eafes 5 and I do not find that it was ever
attended with noxious efFedis.

Of the various fubftances which are ad-
miniftered in putrid difeafes, on account o£
the carbonic acid gas which they contain,
the following are the principal ones, *viz.
effervefcing alkaline and acid mixtures, con-
fifting of a folution of fait of tartar, to
w^hich lemon juice, or diluted vitriolic acid,
or diluted nitrous acid, is added the mo-
^ ment

140 Medicinal Properties of

meat before it is to be drank 3 fweetwort,
or an infufion of malt, yeaft, and certaia
acidulous fruits, fuch as oranges, lemons,
&;c.

I SHALL not attempt to define the cir-
cumftances in which one or other of thofe
articles may be preferable, nor is it necef-
fary to limit the dofes. The circumftances
of fuch cafes being very numerous and di-
verfified, muft be left to the Ikill of the
attending praditioners. If the carbonic acid
gas be adminiftered in the aerial form, the
quantity of it can hardly be too great, pro-
vided it does not diftend the abdomen too
much 3 but if the gas be given in combina-
tion with other fubflances, the quantity of
thofe other fubflances muft be limited, not
by the quantity of carbonic acid gas that
may be contained in them, but by their other
properties, which muft be proportionate to
the ftate of the patient.

It has been propofed (not without ex-
peftations of fuccefs, though with difficulty

of

Factitious Air^. 141

of execution) to introduce, in certain cafes,
the whole body of the patient, the niouth
excepted, into a veiTel full of carbonic acid
gas ; for as this gas is abforbed by the
pores of the Ikin, a greater quantity of it
might thereby be imbibed,

Head-Ach.

THE various ' origin of this diforder,
and the fmall number of cafes that are cir-
cumftantially related, prevent our forming
a comprehenlive idea of the ufe of faditious
airs in cafes of this fort. The inhalation of
diluted oxygen air, has fome times been of
ufe in what is commonly called nervous
Jiead-ach; and it appears that in fuch cafes,
a very great proportion of oxygen air has
been adminiftered, even as much as five or
fix gallons per day. I would not, how-
ever, recommend fo free a ufe of it.

In head-achs that arife from a weak di-
geftion, the inhalation of diluted oxygen air
is an uleful remedy. See the article Digejiion.

Hcemoptyjisy

142 Medicinal Properties of

Hamoptyjisy or Spitting of Blood.

I FIND a few cafes of this diforder,
in which the adminiftration of hydrocarbo-
nate gas was adminiftered with good effed:.
The account of the moft remarkable one
will be found in the next chapter.

Ophthalmia.

IN cafes of ophthalmia, and weaknefs
of fight, when accompanied with a relaxed
habit of body, the inhalation of diluted
oxygen air has been of Angular ufe. About
two quarts (when a fmaller quantity has
proved ineiFedual) of oxygen air, with about
fifteen of common air, is a dofe fufficient
for each day.

Phthi/is Fulmonalis,

See Confumption.

Paralyfs^

Factitious Airs. 143,

Paralyjis.

I FIND a few cafes of that fpecles of
paralyfis which is occaiioned by prepara-
rations of lead, the colica piBomim, where
the inhalation of diluted oxygen air proved
beneficial. Three or four pints of it, with
about thirty pints of common air, is a dofe
fufficient for each day.

Scur'iSy.

THE ufe of carbonic acid gas has long
been confidered as a powerful remedy in
fcorbutie diforders; and certain it is, that
when the diforder is not too far advanced,
a perfedl cure may be generally expedted
from it ; and even in cafes of the worft fort,
the free ufe of this gas has frequently ac-
compliflied a perfed recovery.

All the various ways of admlnlftering
this gas, which have beea mentioned for
the cure of putrid fevers (See the article

FeversJ

144 Medicinal Properties cf

Fevers) are applicable to this fort of dif-

order.

Since much has been written concerning
the fcurvy, and fince the methods of admini-
ftering fuch fubftances as contain abundance
of carbonic acid gas, are generally known
and fuccefsfuUy adminiflered, I fhall not de-
tain the reader with long extracts from
more able writers; but fhall only add, that^
w^hilft the carbonic acid gas is applied to
the ftomach and intpftines, a moderate dofe
of diluted oxygen air ihould be applied to
the lungs by the way of refpiration ; for
whilft the former adls as an antifeptic, and
corredls the putrid tendency, the latter
gives energy and vigor to the fibre, and
enables the body to throw off the morbid
humours with greater quicknefs.

Stone in the Bladder ^ &c.

WATER impregnated with carbonic
acid gas, has been long known to afford
relief in calculous complaints of the bladder

and

Factitious AiR§. 145

land urinary paffage. But by the addition
of a fixed alkali, the remedy has of late been
rendered much moi-e efficacious in cafes of
the above-mentioned fort, and even when a
large flione has adlually exifted in the blad-
der. I do not know how far this acidulous
fodu *water, as it is commonly called, may
operate by way of a folvent of a large flonei
but certain it is, that even in thofe cafes it
affords confiderable relief, and it feems ef-
fediually to prevent the farther accumula«
tion of the ftony matter, by diflblving the
mucus as well as the fmall ftony concre-^
tions, and walhing them off from the kid-
tiies, ureters, bladder. Sec. It is, therefore,
given in all complaints that originate from
a thickening of, or depofition of grofs matter
by, the urine in the above-mentioned parts,
fuch as ftrangury, pain in voiding the urine,
ulceration of the parts, &c;

For this pufpofe one ounce of foda is
diffdlved in four or five pints of rain, or of
boiled foft, water; and th^ folution is then
impregnated^ as miicb as poffible, with

%4 carbonic

146 Medicinal Properties of

carbonic acid gas **. Of this water, a pint
a day is the quantity ufually given for the
above-mentioned diforders, and it is to be
drank not all at once, but at three different
timeS;, ws;. morning, noon, and night.

Independent of thofe difeafes, the aci-
dulous foda water is fuccefsfully admini-
ilered in fccrbutic cafes, biUous complaints,
weaknefs of the digeftive organs, fome ner-
vous afFed:ions, &;c. but in thofe the pro-
portion of the alkali, as well as the daily
allowance, muft be diminiflied according ta
the circumftances of the cafe.

Swellings^

I FIND one cafe only of a white fwel-
ling of the knee recorded, in which a per-

* In Dr. Ncoth's gkfs apparatus for impregnating
water with carbonic acid gas, the quantity of gas that
can be thrown into it is very moderate, yet efficacious ;.
but the foda water which is nov/ prepared and fold in
London by a Mr. Schweppe, contains an incomparably
greater proportion of carbonic acid gaSj and accordingly
is much more efHcacious.v

fed

Factitious Airs, 147

feft cure is faid to have been accompllllied
by the daily inhalation of diluted oxygen
air. As thole fwellings owe their origin
in great meafure to weaknefs of body, it is
likely that the ufe of oxygen, which invi-
gorates the animal fibre, may prove an ufe*
ful remedy*

••

The like treatment is faid to have been
found fometimes ufeful in fcrophulous tu-
mours*

XJkers.

THE faditious airs have been fre*
quently adminiftered in cafes of ulcers on
different parts of the body, and efpecially on
the legs ; but the indifcriminate and inju-
dicious application^ which feems evident in
many cafes, has been produdive of equivo-
cal efFeds. However, a careful examina-
tion of the particular circumftances {hews,
in agreement with the theory, that when
the ulcers originate from a poor ftate of
the blood, and a debilitated habit, the daily
L 2 inhalation

14? Medicii^al Properties of

inhalation of fhree or fbui* pints of oxygeirf
air, with about ten times that quantity cf
common air, is of iingu'lar ufe ; and by this
means' fome ulcers of the Worft kind, viz.
painful, foetid, flubborn, &c. and when
they were accompanied with fcurfy erup-
tions over great part of the body, with
want of appetite, &c. have been completely
cured in about fix weeks time*

In ulcers of other fort the ftate of tl?e
patient, as alfo the origin of the diforder^
muft be carefully attended to, and the elaf-
tic fluids, when they may be thought ufe-
ful, muft be adminiftered accordingly, other-
wife tkey will: produce mofe harm than
good. In fad:, I find a cafe of a fcrophulous
ulcer, where the oxygen air proved detri-
mental \ but a mixture of oxygen, bydro-^
carbonate, and common air, accomplifhed
the cure. This cafe will be found in the
next chapter*

Ir>i all cafes of ulcers, the external appli-^
cation of carbonic acid gas generally aftordi

ant

Fac-tixious x^irs. 149

•an alleyiation of pain, as well as of the fos-
lor, and a better difcharge.

CHAPTER VIIL

Medical Cafes in which Aerial Fluids ^w ere
ndrninifiered,

A COLLECTION of medical eafes, in
which the faditious airs have been
adminiftered with great fuccefs, forms the
content of the prefeiit chapter. Thofe
cafes have been either extracted from other
publications, or they have been comimuni-
cated by intelligent friends % and they have
been feleded out of a great number, merely
for the purpofe of fhewing the pratflical me-
thods of adminifteriag the artificial elaflic
fluids. Such cafes, therefore, have been
preferred, as by the variety of circumftances
feemed more likely to manifeft the modes
pf applying, proportioning, varying, and

L 3 fufpending

150 Medicinal Properties of

fufpending the adminiftration of the fadi^
tious airs.

Convinced that the unlkilful applica-
tion of this new fet of remedies has pro-e-
duced confiderable harm, and has thrown a
degree of difcredit on the pradtice, I take
the liberty of warning the praftitioners
againft drawing hafty ccncluiions from a few
crude, and, in all probability, ill-managed
cafes. For however fldlled thofe gentlemen
may be in other branches of phyfic, it is at
leaft likely that in this new application their
management of patients may not be gene-
rally corred: y and of courfe the failure is
not always to be attributed to the want of
power in the aerial fluids.

Case I.
Communicated by Dr, J. Lind, ofWindJor^

THE firfl: time I applied the modified at-
mofphere as a remedy, was in the cafe of
an offig^r of the Excife, who, during the

(eyere

Factitious Air.s, 151

fevere weather of January, 1797, being
iBuch expofed to the cold intheexercife of his
duty, had got a violent cough, which caufed
the rupture of a confiderable blood veflel
in his lungs, and this v^^as foon followed by
the fymptoms of a rapid confurnption. On
the 25th of January he firft applied to me,
when I ordered him an infulion of rofes,
acidulated with vitriolic acid, and fmall
dofes of ipeca.cuanha, to ftop the hoemoptoe;
and for the cough and hed:ic fever I recom-
mended him to breathe, feveral times in the
courfe of the day, the vapour of vitriolic
ether, in which the powdered leaves of
cicuta were infufed, after the manner re-
commended by Dr. Pearfon, of Birming-
ham. The benefit which he received from
this application was really remarkable, for
after not more than four or five days, al-
moft all the bad fymptoms v/ere wonder-
fully diminiflied ^ yet, finding that he got
hardly any fleep at night, and that he
had been a bad fleeper for above a year,
I made him inhale about a quart of hydro-
carbonate gas, diluted with about fourteen

L 4 quarts

152 Medicinal Properties of

quarts of common air, at bed-time, which
procured him an uninterrupted night's reft,
iuch as he had not experienced for many
months before. He continued to follow the
fame courfe till the 20th of February, when
his health being perfectly reftored, he re-
turned to his duty. — N. B. When he in-
haled the diluted hydrocarbonate, he drew
it in over the fleam of hot water, with the
inhaler which I have conftrudled on the
plan of Mr. Watt's refrigeratory *.

Cas? IL
CGmmunicated by thefame^

I TRIED the diluted hydrocarbonate
like wife with fuccefs, in an inflammation
of the lungs. The patient was a man of
fiXty-fix years of age, labouring under an
inflammation of the lungs, but attended

* This Inhaler is made of japanned tin, and being
filled with hot water, is interpoTed between the bag or
i:ecriver of air and the mouth of the patient, fo that
the air is heated by the vapour of hot water in pailing
through it.

with

Factitious Airs. 153

with fo fiiiali a pulfe tbat bleeding did not
appear advifeable. I therefore direded him
to breathe the hydroearbonate gas, diluted
nearly in the proportion mentioned in the
preceding cafe, which he did every night,
and occalionally whenever the pain return-
ed. The effedt of the modified air was im-
mediate, and very remarkable, for not only
the pain was removed^ but he ufed to fay
that the hydroearbonate had deprived him
qf his body, and had left him only his
head ; fuch was the diminution of irrita*
bility which this gas is capable of pro-
ducing.

The diforder vaniil:ied in a very fhort
time : for in feven days from the com-
mencement of the application, his health
was perfectly reflored.

This cafe fhews that In inflammations of
the lungs, when the pulfe is weak, which
is fometimes the cafe, the reduced atmo-
fpheres are, perhaps, the only application
pradicablq.

Case

154 Medicinal PropePwTies of

Case III.
Related by Dr, CarrnichaeL

Birmingham, March, 1795.

I. B. 2Et. 45,was attacked about four months
fince with difficulty of breathing, attended
dt times with pain under the fternum, and
commonly with a fenfe of tightnefs of the
thorax, frequent cough, with copious ex-
pectoration of a tough whitifh fluid, pulfe
96, body regular^ appetite variable. He
has feldom pafied four and twenty hours
without a material aggravation of all his
iymptoms. Was firft attacked with this
diforder fix years ago, and has regularly
fufFered very feverely from it every winter
lince that period i it has always left him
about the beginning of May, and he has
kept free from complaint during the fum-
mer and autumn months. He has tried
many remedies, but never with more than
very tranfitory relief.

February 14th, 1795, I dired:ed him
to inhale daily a mixture of hydrocarbonate

and

Factitious Airs. 155

and atmcfpheric air, in the proportion of
I to 19. — 15th, No fenfible efFeds frorn.
the ufe of the hydrocarbon ate ^ the ftrength
of the mixture was therefore increafed in
the proportion of two to i8, — i6th. No
vertigo, nor any other fenfible efFedl, pro-
duced by the ufe of the modified air. The
proportion ftill farther increafed to 4 ta
18.-— 17th, Confiderable vertigo produced
by yefterday's dcfe, which returned at in-
tervals, attended by head-ach during the
day. Breathing much relieved, even during
the aft of inhaling the modified air, and has
fince continued tolerably eafy. Slept bet-
ter laft night than he has been accuftomed
to do for fome months. — 22d, Hydrocar-
bonate continues to produce confiderable
giddinefs -, breathing, except fome fhort in-
tervals of flight return, continues much
eafier. Cough lefs frequent, expedora-
tion much diminifhed. Continues to enjoy
comfortable fleep. — 27th, Had a confider-
able return of difficulty of breathing on the
afternoon of the 25th, which, however,
abated fo much before his ufual bed-time,
6 as

1^6 Medicinal Properties of

as not to prevent him from paffing the night
comfortably. Cough infrequent, and rarely
attended with expedloration. Has for fome
time paft had no pain under his fternum, and
rarely any fenfe of tightnefs of his thorax.
— March 4th, He is in every refpedl fo
much better, that he intends to return to
his ufual occupation (making moulds in a
caft- iron foundry) on the 9th inft. Modi-
fied air continues to produce vertigo.---
March 9th, He continued without any re^
turn of his complaint^ and returned to his
employment as he intended ; but after
working for a few hours only, he was
obliged to defift, by a return of the ftnfe of
tightnefs on his thorax, and confiderable dif-
ficulty of breathing. Breathing increafed
in difficulty towards evening, and ftill con-
tinues, attended by frequent dry cough » —
1 3th, Continues to breathe with confider-
able difficulty, pulfe 100 ; fleeplefs nights;
cough more frequent, but now attended
with confiderable expedloration. — 17th,
Difficulty of breathing continued until yef-
terday; has paffed a better night than

ufual I

Factitious Airs. J 57

lafual ; and this morning finds himfelf mucli
better. — 20th, Breathing continues eafier;
cough much lefs frequent, and quantity of
expedoration diminiihed. Has flept for
fome nights paft comfortably; pulfe 86.
Modified air continues to produce confi-*
derable vertigo. — 29th, Continues uniformly
to recover ; his cough is very trifling, and
he exped:orates better; his ftrength is fo
much improved, that he can ufe confider-
able exercife without inconvenience. Sleeps
uniformly welL-— He returns to his work
to-morrow, but for the prefent is to work
within doors. He is of opinion that he is
in every reljpcdt equal to the undertaking.

Case IV.
Related by the fame. >

J.T. set. 40. has for two years paft been
affedted, during the winter and fpring
months, with cough and expectoration, and
at times with pains in his breaft> accom-
panied with flight dyfpncea. Thefe fymp-

toms^

158 Medicinal Properties tf

toms, in general, left him during the fum-
mer months, and never at any time arofe to
fuch a degree as to prevent him from fol-
lowing his ufual occupation. In the begin-
ning of 0(Stober laft he w^as feized with pain
on his fide, cough, dyfpnoea, and after fome
time with copious expedloration. He ap-
plied for my advice in the beginning of
November. At that time he had an almofl
inceffant cough, attended with copious ex-
ped:oration ; he complained of a fenfe of
tightnefs acrofs his thorax, and much dyf-
pnoea on the flighteft exertion 3 his pulfe
was in general from 1 10 to 120, his nights
were reftlefs, and attended with profufe per-
fpirations, his body was irregular, his ap-
petite much impaired, his frame much
emaciated. I ordered for him, at different
times, emetics, fquills, ammoniacum, blif-
ters, &c. but from none of them did he de-
rive more than a very temporary relief.—
November 27th, he began the ufe of the
hydrocarbonate; I direded him at firft to
inhale a mixture containing a quart and a
half of this fpecies of faditious air, and

nineteen

Factitious Airs. 159

nineteen of atmofpheric air. This quantity
he ufed in about twenty minutes, breathing
it for twenty feconds together, and then
reftingfor one, two, or three minutes, ac-
cording to the degree of vertigo produced.
— 2 8th, The vertigo produced by yefterday's
inhalation was very fevere, and returned at
intervals during the evening. He has paffed
a much better night than ufual, and fays
that the dyfpncEa and fenfe of ftri(5lure on
the thorax are much relieved. The quantity
of hydrocarbonate diminifhed to one quart,
diluted as above.— 30th, Cough much re-
lieved, fenfe of ftrifture gone, dyfpnoea lefs
troublefome on motion, has had better
nights, and his perfpirations are lefs pro-
fufej pulfe 106, appetite rather better. —
December 7th, Cough evidently better, ex-
pectoration confiderably diminifhed, pulfe
95, body for fome days paft regular; breath-
ing fo much improved that he can with
eafe walk up flairs to his chamber and un-
drefs himfelf, without return of difpneea,
which he could not before accomplifh with-
out thegreateft difficulty; fleeps better than

he

i6b MEi3iCiNAl Properties of

he has done for months pafl, perfpirations
entirely left him, appetite mended. — i5th^
Continues to recover in every refpedl, has
at times fome return of tightnefs on his
breaft, but which is uniformly relieved of
completely carried off by the hydrocarbo-*
nate. His countenance is evidently altered
for the better, and he is of opinion that his
flrength returns. Notwithftanding that
the modified air ftill continues to produce
confiderable vertigo, I increafed the quan-
tity to two quarts, diluted as before. — 27th,
Cough very much relieved, expectorated
matter reduced to one-third of its former
quantity, pulfe from 84 to 90. He has
evidently acquired fleih, and he is of opinion
that his ftrength continues to improve.— i-
January 6th, 1795, Cough rather more fre-
quent, and attended with fome degree of
difpnoea. On account of the feverity of the
weather, which evidently affedls him, I or-
dered him not to flir from home. At this
time he began to breathe the modified air,
of the ftrength dire<fled above, twice a day.
— 1 6th, Cough relieved, quantity of expec-
torated

Factitious Airs. i5t

torated matter much the fame as reported
on the 27th ult.3 in other refpefts the
fame.T— February ift. On account of the
unufual feverity of the weather, no advance
has been made iince laft report. Cough
more variablcj and at times attended with
fome degree of difpncea, expeftorated matter
increafedj he does not, however, emaciate.
— 1 2th, Cough much abated, quantity of
expedtoration reduced to one-fifth of its
former quantity, his ftrength is fo much
recruited that it is with difficulty I can re«
ilrain him from returning to his occupation.
In every refped: he is much better.— March,
I ft, continues to gain ftrength, cough lefs
frequent, and expedoration ftill diminiihing
in quantity, appetite good, fleeps well. As
I could not prevail with him to remain
longer at home^ I advifed him, before he
returned to his ufual occupation, to walk
out a little daily.

He complied with my advice, and con-
tinued to gain ground till the 9th of that
months when in the evening he was feized
M with

i62 Medicinal Properties of

with the ufual fymptoms of the influenza,
an epidemic catarrhal infedion, which at
that time prevailed much in this place. The
febrile fymptoms ran high, and were at-
tended by frequent cough and confiderable
pain on his fide ; he complained alfo of
fevere head-ach, and unufual langour; he
was thirfty -, his tongue was v/hite, and his
pulfe no. — March 15th, febrile fymptoms
continue 3 cough frequent, but now at-
tended with increafed expedioration 5 pain
of his fide lefs fevere 5 confiderable difpncea
on the flighteft motion ; pulfe 1 1 5, fmall
and weak. Until this attack he inhaled
twice daily a gallon of hydrocarbonate, di-
luted with four times the quantity of atmo-
fpheric air, but, as his fl:rength wafted, it
was found neceflTary to lefi^en the quantity to
one quart diluted as above. — March 20th,
pain of his fide fomething eafier, but his
cough is increafed in frequency, and his ex-
ped:oration more copious. Reftlefs nights;
no appetite ; ftrength fo much impaired
that, for the laft four days, he has not been
able to inhale the modified air 3 pulfe 120.

I direded

Factitious Airs. i6^

I direfted a warm ftlmulating plaifter to be
applied to his fide, and five drops of tinftura
opii to be given every four hours. — 'March
28th, pain of his fide gone, but his other
lymptoms continue; bowels regular; has
had better nights, but his fleep has been at-
tended with profufe perfpirations ; the tinc-
tura opii was omitted, and he was di-
refted to take at nearly the fame intervals a
fmall glafs full of port wine. — April 1 5th,
complaints continue without material altera-
tion. From this date he re-commenced the
ufe of the hydrocarbonate, beginning with
it of the ftrength of one pint to fixteen
quarts of common air.— April 25 th, at fir ft
the modified air occafioned confiderable ver-
tigo, but he foon became fo much habitu-
ated to its operation that the quantity was
increafed to one^ and afterwards to two,
quarts. His perfpirations have abated, his
cough has been lefs urgent, the quantity of
his expe<2:oration has diminifhed, and the
difpnoea, with which he has for fome time
paft been troubled en the flighteft motion,
is greatly alleviated.

M 2 March;

164 Medicinal Properties of

March 3, Since the laft report he has ex-
perienced coniiderable amendment, pulfe
98. The quantity of hydrocarbonate was
furthei- increafed to a gallon, diluted with
four times that quantity of atmofpheric air.
May 15th, he has continued to recover fo
much in every refped;, that yefterday he
was able to walk fourteen miles into the
country.

From this time I did not fee him till
the middle of June, when he returned to
this place with an intention to follow his
ufuai occupation. He was in every particu-
lar fo much better, that he feemed to have
recovered his health completely. I advifed
him, however, to the contrary, to which he
confented, and he has fince been occupied in
hay-making, and more lately in reaping. I
faw him a few days ago ; he cannot be faid
either to cough or expediorate, except in
the morning, and then in the moft trifling
degree, and his ftrength is fo completely
reftored, that he has been earning wages
equal to thofe of the ftouteft of his fellow-
labourers^

Factitious Airs. i6^

labourers, with both eafe to himfelf and
fatisfadion to his employer.

Case V.
Related by Dr. W, Pear/on.

ELIZABETH VYSE, aged 27, having
been feized at the end of autumn with
cough, fever, and fpitting of blood, applied
at the hofpital for relief, and came under
my care lafl Odlober. She informed me
ihe had been fubjed: to a cough for three
winters. She had a quick and fmall pulfe,
flu filed cheeks, dyfpnoea, pain on the fide,
conftant cough attended with copious ex-
pe(floration, and night-fweats. She was
very feeble and much emaciated. The ha^-
m.optoe was foon removed by the medicines
commonly prefcribed in fuch cafes 3 but the
fymptoms continued. I therefore ordered
her, on the 12 th of November, to breathe
the vapour of vitriolic sether, impregnated
with extradt of cicuta two or three times a
day. On the 1 9th, when I faw her again,
flie informed me that (he had obtained great
M 3 relief

'i66 Medicinal Properties of

relief from the aether vapour, having much
lefs tightnefs acrofs the cheft, and lefs J)ain
of the fide. She faid fhe w^as fomewhat
giddy after every inhalation. — December
the 3d, lefs fever, lefs cough, and con-
fiderably better in every refpecft. Has found
more benefit (to ufe her own words) from
the asther application than from any thing
elfe. — December loth, cough and other
complaints fo flight, that fhe fays fhe does
not require any m.ore medicines.

iV. jB. During the ufe of aether vapour,
fhe took a decoftion of Peruvian bark and
farfaparilla, and pills compofed of extradl of
cicuta and rhubarb.

Case VI.

delated by Mr, Barr, Birmingham ^ October g^

1795-

Mr. BARROR, of Barton-under-Need-
wood, being in this town on a vifit to a
friend in the fpring of 1793, was feized
with an highly inflammatory fever, attended

with

Factitious Airs. 167

with a violent pain of the fide. This fever
was followed by a dry tickling cough, a
fenfe of tightnefs in breathing, much lan-
guor, and a great degree of reftleflhefs and
anxiety. His bowels felt full, tenfe, and-
uneafy ; his pulfe intermitted ; and he com-
plained that his urine, though nearly in the
ufual quantity, did not flow freely, and that
he had always the fenfation of not having
evacuated the whole. Blifters, boluffes of
triturated mercury, and a decoftion firft of
Peruvian, and afterwards of Anguftra, bark
were prefcribed. He was relieved by thefe
medicines, but he neither recovered his
ftrength nor his fpirits. In this fituation
nearly he pafled the remainder of the year
in the country; in the fpring of 1794 he
came to Birmingham again, with all the
iymptoms of his diforder increafed, particu-
larly the Gppreffion in breathing. He could
neither lie down in bed with comfort, nor
afcend the fmalleft aclivity without the
greateft uneafinefs. His urine v/as dimi-
nifhed in quantity, and voided with diffi-
culty. A decodtion of Seneka root, an(J
M 4 fmall

i68 Medccinal Properties of

fmall dofes of Digitalis were dire cfted and
continued for two or three weeks ; but they
rather feemed to amufe than relieve him.
He called on me again laft April, and told
me that all medicines had loft the power
pf relieving him, that his breathing was
now more generally difficult, that his urine
was very fcanty, and that his appetite was
entirely gone. I prefcribed the Digitalis
with a itter infulion. He went into the
country and continued thefe medicines for
fome time. Towards the end of July he called
upon me again — but, alas ! how changed !
His face was now become pale and ema-
ciated, his eyes flared as if taking a laft
confcious view of their objed:; which laft
circumftance much alarmed his friends. —
His legs were fwelled to fuch a degree that.
the fkin was become much inflamed, and in
danger of burfting. He had a continual
tenefmus, and made very little urine ; he
could not endure an horizontal pofture for
a moment, but was under the neceffity of
being bolftered upright in bed through the
nighty even then he flept little, and that

little

Factitious Airs, 169

little was difturbed and unrefrefiiing^ for he
frequently ftarted from his ileep under an
impreffion of inftant fafFocation.

Having feen an account of the happy
reUef Sir William Chambers had expe-
rienced from oxygen in a fimilar fituation^
I wrote to my patient, and advifed the
adoption of the pneumatic plan. 1 did this,
I confefs, in the prefent inftance, with little
hope of advantage ; but as the moft power-
ful medicines had produced no falutary ef-<
fedl, I felt it my duty to him, as well as to
the caufe of humanity, to urge this com-
pliance. I procured him a reading of the
cafe, and the fimilarity of the circumftances
was fo ftriking, that he agreed to place
himfelf immediately under my care.

He arrived here on the 12th of Auguft,
and began, to infpire the factitious air on the
13th. I directed one quart of oxygen
mixed v/ith nineteen of atmofpheric air, to
be inhaled every day 5 but as the fymptoms
were becoijie extremely urgent, I thought
4 it

lyo Medicinal Properties df

it right to join the ufe of thofe adive medir-
cines that I had prefcribed for him before.
Accordingly I direded him to take half a
grain of Digitalis in fubftance, every even^
ing, and four ounces of a decodlion of An-
guftra bark in the courfe of each day. On
the third night after infpiring he found
himfelf more compofed, he could remain
longer in one pofture, and the ftartings,
during fleep, feemed both lefs frequent and
lefs violent. Every night he was fenfible
of amendment ; in ten days he could bear
the removal of feveral of the pillows that
bolftered him up in bed ; and he could fleep
for three or four hours without one flarting
fit. The fwelling of his legs too began now
to fublide ^ the tenefmus was entirely re-
moved ; the quantity of urine was much
increafed, and he could walk up ftairs with
much eafe; his appetite and cheerfulnefs
began to return, and the pale face of difeafe
to give place, to the florid countenance of
health. In the courfe of the fecond week
I had gradually increafed the quantity of
oxjgen to two quarts a day, diluted as he-
fore.

Factitious Airs. 171

*^fbre. In four weeks from his beginning to
infpire the vital air, not a veftige of the
diforder remained, except weaknefs ; he
could lay his head as low in bed as when in.
perfeft health, and fleep the whole night -;
no fwelling of the legs remained ; no diffi-
culty of breathing upon ordinary exertion;
and every function was performed with re-
gularity and eafe. He then went home
provided with a pneumatic apparatus, and
diredlions how to ufe it, and laid afide the
ufe of all medicines except a laxative pill
occafionally. He paffed through this town
yefterday in perfedl health. His ftrength,
agility, and vivacity, are greater than in
ipoll men of his age (60).

Case VII.

Related by. Dr. Alder/on, — Hully June ^th^
^795-

MISS — , aged 16, had all the fymp-
toms of approaching phthifis, cold tremors
about twelve o'clock 3 fever, heat, and fluih-

ing

172 Medicinal Properties of
ing every afternoon, pulfe 120, counte-
nance uncommonly florid, breathing rather
difficult, cough fevere, accompanied with
cxpedoration 3 as feveral of her family had
died of confumption, there could be little
doubt of the tendency of thefe fymptoms ;
and after finding nitre, fpermaceti, vomits,
&c. to have no good eiFed:, I advifed the
inhalation of hydrogen air. She therefore
daily inhaled a quart of pure hydrogen
from water, by every now and then taking
an infpiration at the mouth-piece of the
tunnel. It frequently occafioned naufea
and even vomiting. The pulfe fell, the
flufliings and fever fubfided, and the v/hole
train of phthifical fymptoms left her, but
at the expence of her fine florid colour, her
countenance having ever fince been of a
darker tint than before fhe was ilL

Case

Factitious Airs, 173

Case VIIL

Related by Mr. Barr. — Birmingham^ i^tb
March 1795.

ABOUT four months ago, a gentle-
man of this neighbourhood applied to me
for advice in the management of a fcro-
phulous ulcer of confiderable extent. He
had tried various remedies, but had derived
no lafting advantage from any of them.
When I firft vilited him he was v^^ora
dov^n by a long courfe of night- watching*.
The deep-feated pain of the arm vv^as fo
conftant and fevere, that it had in great
meafure deprived him of ileep. His coun-
tenance was pale and iickly; his limbs
were continually afflidled v^ith aching pains;
every exertion, even the moft gentle, feem-
ed beyond the m.eafure of his ftrength, for
his body had lofl: much of its aftive power,
and his mind much of Its wonted energy.
The difcharge from the ulcer was copious,
thin, bloody, and corrofive ; and befides, the

v/hole

174 Medicinal Properties of

whole furface of the fore was fo exceedingly
irritable, that the mildeft dreflings, applied
in the gentlefl: manner, produced very fe-
vere and lafling pain. During the iirft fix
weeks of my attendance, he regularly took
as much Peruvian bark in fubftance as his?
ftomach and bowels could bear ; and the
ulcer was drefled with various emollient,
fedative, and aftringent applications, but
without any permanent advantage. I then
recommended a trial of oxygen air, which
was readily complied with. He began by
infpiring four ale quarts diluted with fix-
teen of atmofpheric air twice a day, and
gradually increafed the quantity of oxygen
to a cubic foot and a half in the day ; by
purfuing this plan for about a month, his
health was wonderfully improved, but the
ulcer fhewed no difpofition to heal. The
deep-feated pain was now entirely removed,
but in the {pace of a few days more he
complained of a burning fenfation over the
whole furface of the fore, fimilar to the
pain arifing from erifepelatous inflamma-
iioii. This unpleafant fenfation firft com-
menced

Factitious Airs. v 17^

menced after infpiring the whole quantity
of oxygen in the fpace of two hours, which
before had been taken in equally divided
portions morning and evening. We ftill
purfued our plan, thinking that this new
pain might be owing to fome accidental cir-
cumftance, ^and that it would foon pafs
away. But it every day continued to in-
creafe, and the ulcer began to fpread wider
and wider. The edges became thick, and
were turned outwards, and the difcharge be-
came more thin and acrid.

In this fituatlon a local application feem-
ed proper. I wifhed to have applied hydro-
carbonate externally to the ulcer, but this,
from fome circumftance of the cafe, was not
pradicable. I then thought to moderate
the ftimulus of the oxygen by a mixture of
hydrocarbonate, which Mr. Watt told me
v/ould occafion no chemical change in the
two airs. Accordingly a mixture of three
parts of oxygen, and one of hydrocarbonate,
was prefcribed. Four quarts of this mixed
air were added to about fixteen of atmofphe-

ric.

176 Medicinal Properties of

ric, and this quantity infpired morning and
evening. In lefs than a week the burning
fenfation was much diminiQied, and the ul-
cer put on a more healing appearance. The
mixed air was then increafed to five quarts,
and ufed as before, which produced an in-
creafe of all the pleafant fymptoms. After
a few days trial of this proportion of the
mixed air fix quarts were pre fcribed. This
is the quantity now infpired morning and
evening.

My friqnd, at prefent, enjoys good health
^nd a good appetite, and feels himfelf as
ftrong as at any former period of his Hfe.
The ulcer is now reduced to lefs than half
its original fize, and healing rapidly. There
is neither fuperficial nor deep-feated pain re-
maining, and the aftion of the contiguous
mufcles is free and eafy.

Case

Factitious Airs. 177

Case IX.

Related by Dr, Redfearn, LynUy Norfolk^
June 26, 1795.

Mr. B. F ■ St, 23, of a florid eom-

plexion, narrow cheft, prominent (houlders,
fmooth ikin, and of a delicate flender form^
has been afflided with haemoptyiis about
two years and a half, attended with dyf-
pnoea, cough, a difagreeable fenfe of burn-
ing in the cheftj and expeftoration of a pu-
rulent nature. Pulie about 100, and inva-
riably accelerated by the hydrocarbonate air.
The hedtic fever was not completely form-
ed, but he had at times a fenfe of chillinefs
in the day-time, with heat tov/ards the
evening. He begaa by taking one quart of
hydrocarbonate, dilated with twenty-one
quarts of atmofpheric air, once a day. From
this mixture he experienced much vertigo
during its inhalation, and two hours after
dinner he fuddenly became vertiginous,
from which, however, he ibon recovered,

N altJiough

17^ Medicinal Properties of

although a violent head-ach remained dur-
ing the reft of the evening.

The following days he only inhaled one
pint of hydrocarbon ate mixed v^dth twenty
quarts of common air, onzo, a day, which
generally afFedled him with fome flight
vertigo and tightnefs over his forehead ; the
hydrocarbonate was increafed gradually to
two quarts or more at one dofe, but I find
it always neceflary to begin with the ori-
ginal dofe, where the air has been recently
generated.

My patient has been perfevering in this
plan about three months, and has had no
return of .the haemorrhage ; his, cough and
expedtoration are very much diminifhed ;
fometimes he does not expedorate more
than one table- fpoonful in the fpace of
three days ^ he has alfo never experienced
any of the diftreffing heats in his cheft,
which barailed him before the admini-
ftration of the air ; his dyfpnoea is perfectly
removed; he can ride upon horfeback twelve

miles

Factitious Airs. ty^

nules without feeling much fatigue j his
appetite is very good, and he lleeps well ;
pulfe §0; he lays he thinks his health is
perfedly eftablifhed,

C A s E X.

IN the month of June 1797, a lady be-
gan the ufe of vital air, for an entire lofs of
voice, which misfortune £he had fuflained
about three years. Her conflitution was
extremely nervous 3 had been the greateil
part of her life lubjed: to deplorable fpaf-
modic affe^Ctions, particularly in the organs
of refpiration, on any trifling exertions of
exercife, or in a confined atmofphere ^ £hc
had been long habituated to an uncommon
quantity of opium, to fufpend the frequency
and violence of her attacks, and many
means had been tried in vain to dimJnifB
materially the quantity (he found neceifary
for her fupport.

She commenced the ufe of the vital air

Tunder the difadvantage of remaining in

N a Londoa

iSo Medicinal Properties of

London during the fummer, a circumftancc
which was likely to be attended with great
aggravation of her complaints, being con-
trary to her ufual practice, and, in fad, (he
had already begun to experience extraordi-
nary fvmptoms of debility from the at-
tempt.

About three quarts of oxygen, with
twelve quarts of common air, v/ere admini-
ftered daily for about a fortnight, the eiFeft
of which was, that a flight degree of tight-
nefs about her cheft came on foon after the
inhalation of the air, and generally went off
in five or eight minutes time ; the pulfc
was likewife rendered fuller though not
more ftequent, and the nights were often
attended with a fort of reftleflhefs. In con-
fequence of this laft effedl it was judged
proper to dim.inifli the quantity of oxygen
air, and accordingly it was found, after re-
peated augmentations and diminutions of
the dofe, that about one quart or three pints
of oxygen air, with about twelve quarts of
common air, was the proportion of the

aerial

Factitious Airs. iSi

aerial fluids, which feemed to agree beft
with her conftitution. This application
was periilled in for upwards of five months,
excepting fome flight intermifljons of a day
or two occafionally, and it produced the
mofl: falutary effefts. The v^hole habit of
body began to be improved in about a
month after the commencement of the ap-
plication. The iliortnefs of breath va-
niflied gradually, as alfo the fymptoms of
debility. Her afped: became healthy, and
the voice improved by flow degrees, fo
that by the end of October its tone was be-
come fully equal to what it ufed to be pre-
vioufly to the illnefs. In fliort, this lady
now enjoys a better ftate of health than £he
has experienced for many years.

A REMARKABLE clrcumfliance was ob-
ferved in this cafe with refpedl to the eff^efl:
of opium, which is, that from long habit (ho
had accufl:omed herfelf to take an extraor-*
dinary quantity of opium daily, in order to
fuftain her ufual exertions of the day ; for,
,in fadt, the opium produced in her rather a

N 3 ferenity

iS2 Medicinal Properties of

ferenity of fpirlts than drowfinefs ; but af-
ter having inhaled the oxygen air for a few
days, file found that fhe could do with lefs
opium, and in procefs of time (lie further
oblerved, that the opium, inilead of fup-
porting, difcompofed her fo much as to
oblige her to diminiih the quantity of it to a
very fmall part of what £he had been ac-
cuftomed to take before the ufe of the ox-
ygen air.

Case XL

"Related by Mr. Hey, in a Lettir to Dr.
Prieftley.

January 8th, Mr. LIGHTBOWNE, a

young gentleman who lives with me, wa§
feized with a fever, which, after continu-
ing about ten days, began to be attended
with thofe fvmptoms that indicate a pu-
trefcent ftate of the fluids.

1 8th. His tongue was black in the
morning when I firfl: vifited him, but the

blacknefs

Factitious Airs. 183

blackricfs went off in the day-time upon
drinking ; he had begun to doze much the
preceding day, and now he took little no-
tice of thofe that were about him; his
belly was loofe, and had been fo for fome
days ; his pulfe beat 1 1 o ftrokes in a mi^
nute, and was rather low ; he was ordered
to take twenty-five grains of Peruvian bark
with five of tormentill-rcot in powder every
foqr hours, and to ufe red wine and water,
cold, as his common drink.

59th. I WAS called to vifit him early in
the morning, on account of a bleeding at
the nofe which had come on ; he loft about
eight ounces of blood, v/hich w^as of a loofe
texture ; the hemorrhage was fuppreffed,
though not without fome difnculty, by
means of tents made of foft lint dipped in
cold water ftrongly impregnated with tinc-
ture of iron, which were introduced within
the noftrils quite through to their pofterior
apertures, a method which has never yet
failed me in like cafes. His tongue was
now covered with a thick black pellicle,

N 4 which

184 Medicinal Properties of

which was not diminifhed by drinking ; his
teeth were furred with the fame kind of
fordid matter, and even the roof of his
mouth and fauces were not free from it ; his
loofenefs and ftupor continued, and he was
almoft inceflantly muttering to himfelf \ he
took this day a fcruple of the Peruvian bark
with ten grains of tormentill every two or
three hours ; a ftarch clyfter, containing a
drachm of the compound powder of bole,
without opium, was given morning and
evening; a window was fet open in his
room, though it v/as a fevere froli, and
the floor was frequently fprinkled with vi-
negar.

20th, He continued nearly in the fame
flate ; when rou fed from his dozing, he ge-
nerally gave a fenfible anRver to the quefr
tions afked him, but he immediately re-
lapfed, and repeated his muttering. His
fkin was dry and harih, but without pete^
chice. He fometimes voided his urine and
fceces into the bed, but generally had fenfe
enough to afk for the bed-pan. As he now

naufeate^

Factitious Airs. 185

naufeated the bark in fubftance, it was ex-
changed for Huxham's tindare, of which
he took a table -fpoonful every two hours in
a cup full of cold water ; he drank fome-
times a little of the tindure of rofes, but his
common liquors were red w^ine and w'ater,
or rice-water and brandy acidulated with
elixir of vitriol; before drinking he was
commonly requeued to rinfe his mouth
with water, to which a little honey and vi-
negar had been added. His loofenefs rather
increafed, and the llools were watery, black,
and foetid; it was judged neceffary to mo-
derate this difcharge, which feemed to fink
him, by mixing a drachm of the theriaca
(indromachiy with each clyfter.

2ift, The fame putrid fymptoms re-
mained, and 2.fubfiiltus tendiniim came on ;
his ftools were more foeeid, and remarkably
hot; the medicine and clyfters were re-
peated.

Reflecting upon the difagreeable ne-
ceffity we feemed to lie under of confining

this

iS6 Medicinal Properties of

this putrid matter in the inteilines, left the
evacuation fhould deftroy the vis vitce be-
fore there was time to correct its bad qua-
lity, and overcome its bad effects, by the
means we were ufing, I confidered that,
if this putrid ferment could be more im-
mediately correded, a flop would probably
be put to the flux, which feemed to arife
from, or at leail to be increafed by it, and
l^i^fomes of the difeafe would like wife be
in a great meafure removed : I thought no-.
thing was fo likely to effedt this as the in-
trodudion of fixed air into the alimentary
canal, v/hich, from the experiments of Dr.
Macbride, and thofe you have made fince
his publication, appears to be the moil
powerful corrcd;or of putrefadion hitherto
known. I recolleded what you had re-
commended to me as deferving to be tried
in putrid difcafes; I mean the injedion of
this kind of air by way of clyfter, and judg-
ed that in fhe prefent cafe fjch a method
was clearly indicated.

The next mcrning I mentioned my re-
fledicns to Dr. Hird ana Dr. Crowther,

who

Factitious Airs. 287

^jho kindly attended this young gentleman
at my requeft, and propofed the following
niethoH of treatm.ent, which, with their ap-
probation, was immediately entered upon.
We firfl; gave him five grains of ipecacu-
anha, to evacuate, in the mofteafy manner,
part of the putrid colluvies ; he was then
allowed to drink freely of brills orange-
wine, which contained a good deal of fixed
air, yet had not loft its fweetnefs. The
tindlure of bark was continued as before,
and the water, which he drank along with
it, was impregnated with fixed air from the
atmofphere of a large vat of fermenting
wort, in the manner I had learned from
you. Inftead of the aftringent clyfter, air
alone was injeded, colled:ed from a fer-
menting mixture of chalk and oil of vi-
triol : he drank a bottle of orange-wine in
the courfe of this day, but refufed any other
liquor, except water and his medicine j two
bladders full of fixed air were thrown up in
the afternoon.

i88 Medicinal Properties of

23d, His ftools were lefs frequent ^ their
heat' likewife, and peculiary^^d?r, were con-
fiderably diminished ; his muttering was
much abated, and tht fubfultus tendiniim had
left him. Finding that part of the air was
rejecled when given with a bladder in the
ufual way, I contrived a method of injeding
it which was not fo liable to this inconve-
nience. I took the flexible tube of that in-
flrument which is ufed for throwing up the
fume of tobacco, and tied a fmall bladder
to the end of it that is connected with the
box made for receiving the tobacco, which
I had previoufly taken off from the tube ;
I then put fome bits of chalk into a fix-
ounce phial until it was half filled ; upon
thefe 1 poured fuch a quantity of oil of vi^
triol as I though capable of faturating the
chalk, and immediately tied the bladder,
which I had fixed to the tube, round the
neck of the phial ; the clyfler-pipe, which
was faftened to the other end of the tube,
was introduced into the anus before the
oil of vitriol was poured upon the chalk.
By this method the air pafiTed gradually into

th<?

Factitious Airs. 189

the Inteftines as it was generated, the re-
jection of it was in a great meafure prevent-
ed, and the inconvenience of keeping the
patient uncovered during the operation was
avoided.

24th, He was fo much better that there
feemed to be no neceffity for repeating the
clyilers ; the other means were continued.
The window of his room was now kept
fhut*

25th, All the fymptoms of putreicency
had left him ; his tongue and teeth were
clean ^ there remained no unnatural black-
nefs o'ifcetor in the ftools, which had now
regained their proper confiftence ; his doz-
ing and muttering were gone oft, and the
difagreeable odour of his breath and per-
fpiration was no longer perceived. He
took nourimment to-day with pleafare,
and, in the afternoon, fat up an hour in his
chair.

His

i^o MEDiciNAt Properties of

His fever, however, did not immediately
leave him ; but this we attributed to his
having caught cold from being incauti-
oufly uncovered when the window was
open, and the weather extremely fevere;
for a cough, which had troubled him in
fome degree, from the beginning, increafed^
and he became likewife very hoarfe for fe-
veral days, his pulfe at the fame time
growing quicker ; but thefe complaints alfo
went off, and he recovered, without any
return of the bad fymptoms above-men-
tioned.

Case XII.
Related by Dr. Thomas PercivaL

ELIZABETH GRUNDY, aged kvtn-
teen, was attacked, on the loth of Decem-
ber, with the ufual fymptoms of a conti-
nued fever. The common method of cure
was purfued, but the difeafe increafed, and
fooii affumed a putrid type.

On the 23d, I found her in a conftant

delirium, Vv^ith a Jubjultus tcndinum. Her

* fkin

Factitious Airs. igt

ikin was hot and dry, her tongue black, her
thirft immoderate, and flools frequent, ex-
tremely oftenfive, and for the inoft part in-
voluntary. Her pulfe beat 1 30 ftrokes in a
minute ; flie dofed much, and was very
deaf. I dire6ted wine to be adminiftered
freely j a bliiler to be applied to her back;
the pediluvium to be ufed fsveral times in
the day, and fixed air to be injected under
the form of a clyfter every two hours. The
next day her ftools were lefs frequent, had
loft their fcetor, and were no longer dif-
charged involuntarily; her pulfe was re-
duced to 1 10 ftrokes in the minute, and
her delirium was much abated. Diredlions
were given to repeat the clyfters, and to
fupply the patient liberally with wine.
Thefe means v/ere afliduouily purftied feve-
ral days, and the young woman was fo re-
cruited by the 28th, that the injeclions were
difcontinued. She was now quite rational,
and not averfe to mefiicine. A decodiion of
Peruvian bark was therefore, prefcribed, by
the ufe of which flie fpeedily recovered her
health.

Case

192 Medicinal Properties of

Case XIII.

Communicated by an intelligent Gentleman in
the Weji of this If and.

A YOUNG lady of i8, the daughter
, of a neighbour of mine, had been long indif-
pofed with a fort of diforder which the
X medical gentlemen of the neighbourhood
could neither properly define, nor in the leaft
relieve. The origin of this indifpofition is
attributed to a violent cold, which this
young lady caught about two years ago at
a ball ; for fince that time fhe had never
enjoyed her health, and, in fpite of all
medicines, fhe rather loft ground by flow
degrees than fliewed any appearance of
an^endmenl. The fymptoms, as nearly as I
can defcribe them, were as follows :

She had loft all colour from her face and
hands, had a remarkably keen appetite, and
eat much mere than other perfons of her
age are wont to do ; but this food gave her
neither ftrengtb nor increment, and fhe

conflantly

Factitious Airs. 193

conftantly complained of wearinefs, refufing
to take any fort of exercife. At night flie
frequently had a flight fever, which termi-
nated by the morning with an head-ach j
but this fever did hot come on every night,
hor did it feem to follow any determinate
period. She perfpired profufely every night,
arid even in the day-time the leail exertion
would throw her into a profufe perfpira-
tion. She had tried bark, fteel medicines,
inineral waters, flight emetics, rhubarb^
&c. but all iri v^in. ^

In this fl:ate of things I firfl: took the
liberty of recommending the ufe of the
vital air, or oxygen air, concerning which
much has been faid df late, and to the
phyfical properties df which I had two
years ago been witnefs in a courfe of che-
inical ledlures, which I attended in Lon-
don. After feveral converfations wath the
father of the young lady on the fjbjedt, it
was at kfl: agreed to try the oxygen air,
and I undertook to perform the experiment
with a few chemical veffels which I hap-
pened to have by me.

O On

194 Medicinal Properties of

On the tenth of April, 1797, I put eight
ounces of nitre in a fmall and luted green
glafs retort, and by expoiing the retort to
a barely red heat, I obtained nearly two
quarts meafure of oxygen air, which, being
mixed with about eight quarts of common
air, was given to the young lady in an
awkward manner ^ for it was introduced
into an old glafs receiver of an air pump, to
the upper aperture of which a leathern tube
was adapted, with a glafs tube at the extre-
mity jsf the leathern pipe, to which the pa-
tient applied her mouth, &c*

The efteftof this application was rathei'
difcouraging. The young lady felt a tight-
nefs, as ihe expreffed it, about her head, for
at leait three hours after the inhalation of
the vital air, and was very reftlefs at night,
in confequence of which flie could not be
prevailed on to repeat the inhalation forfeve^
ral days. At laft, finding that no other bad
confequence had been produced by it, fhe
confented to make another trial, which was
managed nearly in the faiPie manner; but it
I was

Factitious Airs. 195

was attended with much lefs tightnefs about
her head, though with an equal degree of
reftlefsnefs at nighty notwithftanding which
a third attempt was made on the following
day, and the operation v/as again repeated
after an interval of one day.

All thofe trials were more or lefs attend-
ed with the like effedts as the firft ; yet our
patient thought that, notwithftanding the
reftlefs nights which ihe had pafTed, her
ftrength feemed to be in fome meafure im-
proved, which encouraged us all to follov/
the application ; and in order to avoid both
trouble and expence as much as poffible, we
procured one of Mr. Watt's apparatufes
from Birmingham, and fome good man-
ganefe from Devonshire, with which we be-
gan to work in a large and more expedi*
tious'v^ay.

We found that Mr. Watt's apparatus re-
quires a nicety of management, without
which one may do rnore harm than good.
In the firft trial of this apparatus we got^
O 2 inftead

196 Medicinal Properties of

inftead of pure a.r, an exolouve elaftic flaid^
for on lowering a lighted match into a
bottle full of it, the air took fire and ex-
ploded. It was foon found that this infiam—
mabihty was occafioned by the moiilure
"which was contained in the manganefe, in
confequence of which the manganefe Vi^as
made very dry for the fubfequent trials, and
thus we obtained abundance of oxygen air,
which was freed from the carbonic acid air
by wafhing in lime water.

Being now in poileffion of the proper
materials, and having feme expedlation of
fuccefs, we began, on the 22d of May, to
work affiduoufly and regularly ; and I took
care to note, every three or four days, all the
circumftances that feemed at all remarka-
ble.

Three pints of oxygen air and eight
quarts of common air were adminiftered
daily, which conftantly produced the tight-
nefs of the head and the reflleffacfs at

night,

Ma IT

Factitious Airs. 197

May the 28th, the young lady fecmed
to have gained ftrength ; but coniplaiiiing
much of the tightnefs of her head, the
quantity of oxygen was diminifhed to one
quart, with eight quarts of common air, per
day, which was continued until the loth of
June, by which time her ftrength was un-
queflionably improved, and the perfpiration
at night was confiderably diminifhed ; but
as a cough happened to come on, we inter-
mitted the application of the vital air for a
whole week, after which, the cough hav-
ing difappeared, the inhalation of the air
was recommenced, and continued as be-
fore.

By the beginning of July the good effedls
of our application were very coniiderable.
The ftrength of the young lady was fuch as
might be expeded in a perfon of her time
of life ; the healthy colour was in great
meafure returned to her face and arms ; the
pprfpiration at night was trifling, and flie
feemed to acquire fiefh.

O ^ Ok

198 Medicinal Properties of

On the 15 th of Augufi:, the inhalation of
the diluted oxygen air was difcontinued,
finding that the young lady's health was
completely reflored.

Case XIV.

A GENTLEMAN, 35 years of age, of
a fcorbutic habit, and fubjecl to violent
head-achsj was induced to try the artificial
airs in December 1796, every other medi-
cal application having proved inefFed:ual,
and his health gradually declining. He was
at firfi: advifed to try the diluted oxygen
air, which he accordingly did, but after
three days inhalatio:: of this air, a confidera-
ble degree of mflammation on his lungs
obliged him to defift.

The inflammation being fubdued, he
again inhaled the oxygen air, and a fimilar
effect took place, though this iecond time
the infiammation was not fo confiderable.

Finding, therefore, that the oxygen air
was not fit for him, he was recommended to

drink

Factitious Airs. 199

drink the v/ater impregnated with carbonic
acid gas, and to take fome other medicines
of a demulcent kind. By following this plan
for about fix weeks, and by breathing the
falubrious air of Devonfliire, his health im-
proved to a ceri.ala degree ; the fcorbutic "
fymptoms were reduced, and the head-achs
were not quite fo frequent as they ufed to
be ; but after this improvement, the con-
tinuance of the above-mentioned medicines
for full three months produced no other
eifea.

Considering that in this improved
ftate his conftitution might, perhaps, bear
the ftimulus of the vital air better than it
hard dene before, he was recommended to
try that air again, but to take it in fmaller
quantities. Accordingly he inhaled not
more than one pint of it with about fixteen
pints of common air every day, which, not
producing any inflammation upon his lungs,
he continued for upwards of two months,
at the end of which tim_c his head-achs
were quite vanifhed, his digeftion, which
O 4 had

20Q Medicinal Properties of

had always been defedive, was confiderably
improved, and |ie reckoned himfelf quite
well.

IN the account of the preceding cafeSj^
the reader njay obvioufly remark, that not
one unfuccefsful cafe has been introduced y
on which it will be proper to mention, that
in fo doing I did not mean to imprefs the
reader's mind with an exaggerated idea of
the power of fac^litious airs , but that my
only meaning was, to render him better aic-
quainted with the practical adminiftration^
of the aerial fluids, which feemed more
likely to be accompliQied by adducing
examples, in which the pradice was in
fome mealure fandioned by fuccefs, than
otherwife.

With refpeft to the eftimate of the effi-
cacy of factitious airs in different diforders,
my reader mufl confult the pieceding chap-
ter j for 1 have exprefied in it the refult,
pr what feem-ed to be the fair refult of

all

Factitious Air§. 2qi

all the cafes that have come to my notice ;
and of fuch caics the f e , v that are con^
tained in the preceding pages form a very
fmaji part.

I WOULD not be underftcod to mean, that
the appUcation of the aerial fluids. In the
cafes of the prefent chapter, is to be con-
fidered as the model of pradical perfed:ion,
for in fome of them the adminiftration is
evidently incorred: 3 but they certainly give
a great infight into the praftice, and hope
that, with the affiftance of the cautions and
rencarks of the foiiowing chapter, they may
in great meafure prevent the abufe of a new
fet of remedies, which have all the ap-
pearance of becoming very ufeful tools in
the hands of fkilfu] praditioners.

2©a Medicinal Properties of

C H A P T E P. IX.
Practical Remarks, Hints, 6cc.

Concerning the ProduSfion of Fadlkious Airs,,

IN particular fituations the difficulty of
procuring proper materials and proper
tools may prevent the poflibility of adopt-
ing the moil expeditious, or, upon the
whole, the moft advantageous, methods of
procuring the aerial fluids ; and when that
is the cafe the practitioner muft confult the
iiril chapter of this effay, for the method
which may be mere fuitable to the circum-
ftances of his fxtuation. But when there is
the opportunity of procuring both materials
and inftruments, it is then proper to follow
the plan which may appear iefs excep*
tionable.

The che^ipeft article for the production
of oxygen air is the mineral called manga--

nefe.

Factitious Airs. 203

nefe^ which is found plentifully In many
parts of this ifland, and elfewhere. A very
good fort of it is found near Exeter. It
ought to be free from extraneous^ and par-
ticularly noxious, minerals; but it fre-
quently contains a confiderable proportion,
of calcareous matter, which may be de-
ted:ed by powdering a little of the mineral,
and pouring fome nitrous acid upon the
powder; for this will produce an effervef-
cence proportionate to the quantity of cal-
careous matter. It muft not, howei^er, be
expeflied to find manganefe perfedlly free
jfrom it ', for though this may be the cafe
with fmall pieces of that mineral, yet in
confiderably large quantities of it, fuch as
are required for the produdlion of oxygen
air, fome calcareous earth is almofi: always
contained ; but the only effed: which arifes
from it, is the produdion of carbonic acid
gas, together with the oxygen air, the for-
mer of which is eafily feparated from the
latter by the well-known method of wa{h-
ing in lime-water.

The

204 Medicinal Properties of

The greateft quantity of oxygen air is
extricated from manganefe merely by the
adion of a full red heat ; it is, therefore,
neceflary to put that mineral in a veflel
capable of refiiling the adion of fuch a de-
gree of heat. Earthen-ware and certain
metals are the materials fit for the con-
ftrudtion of fuch veffels. The former is cer*
tainly unexceptionable in pomt of purity;
but it is not managed very eafily for this
purpofe, and befides, the ufe of it is at-
tended with confiderable expence, for a
veffel of that fort will hardly ever ferve
more than once, as on cooling after the
firft experiment it generally breaks y and
indeed it frequently breaks in the courfe of
the experiment. Of the metals, gold or
piatina veffels would be the fitteft for the
purpofe, did not their value offer a ma-
terial objedion. Thofe metals excepted,
iron is the beft ; for though the ufe of a
veffel of this metal be attended v/ith evi-
dent objections, yet, when managed with
care and attention, the oxygen air may be
produced of fuch a degree of purity as to be

more

Factitious Airs. 205

more than fufficiently ufeful for medicinal
purpofes.

It is neceffary to remark, that in all
cafes, birt efpecially when an iron veffel is
ufed, the manganefe, as vvqW as the veffel in
which it is contained, and the pipe or tube
which conveys the air from it to the receiver,
muft be quite free from anirnal or vegeta-
ble matter, and perfectly dry, otherwife the
elaftic fluid, which is produced, may be in-
jured in point of purity, and it may even
degenerate into a noxious ^fluid.

When thofe particulars are attended to,
the oxygen air will principally contain a
certain proportion of carbonic acid gas, and
fome light powder of manganefe, the for-
mer of which is to be feparated by mears
of lime, and the latter will be depofited
by ftanding, in about ten or fourteen hours
time.

The fpeeies of inflammable gas moflly
in ufe are extraded by means of diluted

vitriolic

2o6 MedicixMAL Properties of

vitriolic acid from zinc or iron, and by
paffing the fteam of water over the furfacc
of red hot zinc, or iron, or charcoal.

The gas, extracfled by means of diluted
acid, holds in fufpenfion fiiiall particles of
the metals concerned, viz. of the ^inc or
the iron, the latter of v^hich in particular
may be rendered manifeft by burning the
gas in a bottle full of it, in which cafe
fome fmall particles of a dark red light will
be difcerned within the pale flame of the
gas, v^^hich are the fenugineous particles i
for thofe minute red fparks are not to be
feen in the inflammable gas which is ob-
tained from pond v/ater, or putrid matter, or,
in ihort, from fiich fubfl:ances as do not
contain any metallic fubfl-ance.

Th e gas obtained by paffing the fleam
of water ever red hot zinc, holds in fuf-
penfion a confiderabie quantity of the
flowers of zinc, which it depoflts in about
a day's time.

The:

FACTiTicus Airs, 207

Th e gas obtained in a fimilar manner
from iron is the moft abundant, and of
courfe the cheapeil.

For the produdion of the heavy inflam-
mable gas, or hydrocarbonate, Mr. Watt
recommends to ufe '^ charcoal made of the
*^ twigs of fofter woods, fuch as willow,
" poplar, hazle, birch, or fycamore, avoid-
*^ ing fuch as have refinous or allringent
" juices. Prepare the charcoal by heating it
** to full ignition in an open fire, and
" quenching it in clean water, or by filling
" a crucible with it^ covering it with clean
" fand, and expofing it to a ilrong heat in
** an air furnace, and then fjfFefing it to
*' cool. In either of thefe cafes it w^ill be
*^ found free from any bituminous matter,
"which might contaminate the air, as ge-
" nerally happens with common charcoal.'*

Mr. Wat t like wife mentions, amongft
other forts of inflammable gas, that which
is extracted from a inixture of charcoal
powder and flaked lime,- which, on ac-=

count

ijo8 Meijicinal Properties of

count of Its peculiar properties feems likely
to prove very lifeful : " In refpe(ft. Jays hcy
" to the medicinal properties, all I know is,
*' that the inflammable air from charcoal
** and lime contained no fixed air feparable
•^ by wafhing with quick lime and water,
*' and that it did not cauf^ vertigo when iii-
" haled pure/*

One or other of thofe fpecies of Inflam-
mable gas may be preferred in particulaf
cafes, and It is not only likely, but in
great meafure proved by adtual experiment^
that the particles of iron, oi* other matter^
v^hich are fufpended in a particular fort of
gas. may be peculiarly ufeful in certaiii
difeafes.

In the produdion of inflammable gas, the
introducftlon of any extraneous matter, and
efpecially of vegetable or animal fubftances,
and of minerals that contain acids, Ihould
be carefully guarded againft. It is likev/ife
advifable, for a very obvious reafon, not to
condudl this procefs by candle light.

ThS

Factitious Airs, 209

The carbonic acid gas may be extraded
from chalk in Mr. Watt's apparatus, ac-
cording to the diredlions given with the
faid apparatus 5 but when no extraordinary
large quantity of it is required, it is far
more commodious to extradl it from chalk
or marble powder, and diluted vitriolic acid>
in a glafs veffel. The difference between
chalk and marble in this refpedt is, that the
former gives out the gas^ quicker, but is
foon exhaufted ; whereat the latter gives it
out more gradually, and for a greater length
of time ; hence, in fome cafes, the former,
and in others the latter, may be preferred.

Concerning the Prefervation g/ Aerial Fluids i,

OXYGEN Air Is not contaminated by
keeping in glafs receivers, or in fuch vefTels
as do not comm.unicate any thing to It, nor
does the contact of pure water injure it^
but in wooden veffels, or VfefTels painted
with oil paint, and when a confiderable
quantity of common river water is in con^

P ta<ft

^10 Medicinal Properties of

ta6l with it, the oxygen air will be conta-
minated more or lefs.

The various fpecies of inflammable gas
are apt to degenerate in procefs of time, efpe-
cially if they be kept mixed with common
or With oxygen air. The hydrocarbonate,
in particular, is vaftly more powerful when
frefli made, than two or three days after.
Due allowance, therefore, muft be made for
the lofs of power in the adminiftration of
thofe airSi

When oxygen air, or inflammable gas,
is to be taken out of an air-holder or bottle,
&c. by putting water in the vefl^el after the
ufual manner, it is advifable to ufe lime-
water; for the lime will not only abford
any carbonic acid gas that may be mixed
with thofe airs, but will alfo prevent the
putrefadiion of the water.

■*
, For this purpofe there is no occafion to
filtrate the lime-water, as is pradtifed in the
ufual manner of preparing it j but it will

be

Factitious Airs. 211

he fufficient to mix the quick lime with
the water, and after leaving it at reft for an
hour or two, to feparate the fluid and ufeful
part from the fediment, by decanting it
gently.

The carbonic acid gas is not contami-
nated by keeping ; but as it is abforbed by
moft fluids, it fhould not be kept in contad:
with much water. In moft cafes it will be
better to produce it afrefti every time it is
wanted.

In order to manage the aerial fluids with
the greateft propriety, the practitioner
fhould make himfelf acquainted with the
modes , of afcertaining their purity. This
may, in great meafure, be derived from
what has been mentioned towards the be-
ginning of this eflfay ; but if a n^ore parti-
cular defcription of thofe methods be re-
quired, and efpecially concerning the ufe of
the nitrous-gas eudiometer, or phofphoric
eudiometer, the reader muft confult thofe
books which have been written exprefsly

P 2 Oil

212 Medicinal Properties oj

on the fubjedl of aerial fluids, as the ad-
dition of thofe methods would increafe the
bulk of this eflay beyond its prefcribed li-
mits.

Concerning the AdmimJt7^ation of Fa5iitious
Airs.

When oil-iilkbags or bladders are ufed,
the air or mixture of airs fhould be intro-
duced immediately before it is to be in-
haled, in order to avoid the airs acquiring an
unpleafant flavour.

The oil-filk bags, when not ad:ually in
ufe, (liould be hung up by means of a fl:ring,
which may be faftened to the pipe, or they
may be put over the back of a chair ; but
they mufl: not be folded or prefixed.

In the ufual way of making the mixture
of airs, the faftitious gas, in any required
quantity, is firfl introduced in the bag, after
which the common air is forced in by means
of a common pair of bellows, until the bag
6 is

Factitious Airs. 213

is quite inflated ; for when the capacity of
the bag is once known, one may eafily de-
termine the quantity of oxygen or other fac-
titious air, which may be required in order
to form a mixture in any given proportion.

When common bellows are ufed for
this purpofe, care Ihould be had that they
be made free from dull and afhes, which are
generally contained in fuch bellows as are
ufed for common fire-places.

When a perfon is inhaling any fpecies
of inflammable gas, or the vapour of ether,
the operation fliould be conduded at a
difl:ance from a candle, left the gas fhould
catch fire, and at leaft^ occafion a fur-
prife.

The quefliion, which is frequently aflced,

whether a patient muft be confined to his

houfe, or to any particular diet, whilft he is

under a courfe of aerial application, fug-

gefl:s the propriety of obferving, that there

is no particular confinement or diet required

xnerely on that account.

P J Wh^m

214 Medicinal Properties of

When aerial fluids are adminiftered, it is
proper to feel the patient's pulfe both be-
fore and after the inhalation, at leaft for
the three or four firft inhalations, as there-
by one may, in great meafure, be informed
of the efFed; which the aerial fluid is likely
to produce, and may regulate the fubfequent
applications accordingly.

^The patient (houldhe enjoined to breathe
the mixture of aerial fluids in an eafy and
natural way, and not in a forced manner, as
fome are apt to do.

With fome perfons the fenfibility of the
lungs is fo very great, that they are affeded
with the fenfation of preternatural heat, and
even of inflammation, by a remarkable fmall
quantity of oxygen j half a pint of it, mixed
with about twenty times that quantity of
common air, has been known to produce
fuch an efl^ed: ; and this obfervation has
been made where there was not the leaft
appearance of mifl:ake, or of any equivocal
circumftance. This is particularly the cafe

with

Factitious Airs. 215

with perfons that have recently recovered
from an inflammation of the lungs. In fuch
cafes, therefore, the praditioner ought to be
particularly careful, and he ought to begin
by adminiftering very fmall quantities of
oxygen.

The above-mentioned fenfation of heat
generally comes on im.mediately after the
inhalation, but fometimes it comes on fome
hours after, and efpecially in bed. It is,
therefore, neceifary to enquire whether any
particular cffcdc has been obferved at any
time between one inhalation and the next,
in order to form a proper eftimate of the ef-^
feCi of the application.

When this fenfation of heat or reftlefs-
nefs is in a trifling degree, the daily inhala-
tion may be continued 3 but it mufl he fuf-
pended, or at leaft moderated, whenever it
be found to increafe by daily repetition.

What has been obferved with refpedl
to the efFed of oxygen air, may, with pro-

P 4 per

2i6 Medicinal Properties of

per and obvious changes, be alio applied to
the inhalation of other aerial fluids, and par-
ticularly of the hydrocarbonate.

However ftrange and unaccountable
fome of thefe efFed:s may appear, as that
produced by a very fmall quantity of an
aerial fluid in certain circumilances ; or that
of the preternatural heat coming on fo long
after the inhalation, (Jcc. my reader may reft
aflfured that the fads are true ^ and though
we cannot reconcile the phasnomena with
the theory, yet as long as abfurdity does not
intervene, we muft not deviate from the path
which is pointed out by. experience, becaufe
we are unable to undcrftand the real caufes
of the eifefts,

APPEN.

Factitious Airs. ^2^17

APPENDIX.

On the Nature of Blood,

TH E intimate connexion between re-
fpiration and the ftate of the blood,
the necefiary dependance of animal life on
the oxygen part of the atmofphere through
the intermediation of that fluid, and the va-
rious difcordant opinions which have been
entertained concerning the nature of blood;
will eafily excufe the introduftion of this
concife account of the nature of that fluid in
the prefent work, whofe principal objedt is
the invefl:igation of the adlion of aerial fluids
on the human body.

The name of blood has been ufed in a
ITiOre or lefs extended fenfe by diflerent

wTiters.

2iS Medicinal Pkoperties of

writers. Some confine it to the red fluid,
which circulates through the veins and the
arteries of the animal body ; others have,
with propriety, extended it to that fluid,
which, whether coloured or colourlefs, is
the moil abundant in the animal body, and
upon the circulation of which the life of
the animal principally depends 5 hence the
red colour is not an abfolute chara6lerifl:ic
of blood; and, in fadl, the blood of certain
animals has not the leafl: tint of red. Laftly,
the name of blood has been beftowed even
upon the fluid which circulates through the
vefTqls of plants.

In the following pages we fliall extend
our obfervations not farther than the red
blood, and hardly beyond that of the hu-
man fpecles ; confining purfelves princi-
pally to the account of fads that are inde^
pendent on particular opinions.

This fluid, fo eflTentially neceflary to
animal life, has been examined with all the

ingenuity

Factitious Airs. 219

ingenuity of man in a mechanical and phy-
fiological fenle, as it circulates through the
veffels of the body ; it has been carefully
viewed, under a variety of circumftances,
through the moft powerful microfcopes,
and it has been analyzed by the m.oft inge-
nious chemifts. By this means many dif-
coveries have been made, and many doubts
have been cleared relatively to it ; but after
all we can form a very inadequate idea of
its extenfive ufe and properties. We muft,
however, remain fatisfied with the prefent
knowledge of fafts, and muft leave the far-
ther inveftigation of the fubjed: to the la-
bours and fortune of future obfervers.

Blood is a flaid coniifting of a great
variety of ingredients, fome of which are
always to be found in it ; whilft others are
adventitious, or are to be obferved in it in
particular circumftances 5 but the propor-
tion of them all is not only various in diffe-
rent ages, and fexes^ and ftates of the body,
but is not the fame even in the different

parts

t2o Medicinal Properties of

parts of the fame body ^. A difference not
fo great with refped: to the number, as with
refpeft to the proportion, of the ingredients,
has been obferved between the blood of
man, and that of other animals, fuch as thq
ox, the horfe, the fheep, the hog, &c.'f'.

Leaving it to the phyfiologifts to ex-
plain how the blood circulates through
the fanguiferous veifels, how the chyle is
mixed with it, how a variety of fluids are
fecreted from it, &c. we fhall examine its
nature as a fluid out of the body.

Blood is of a uniform rich red colour,
which inclines towards the florid vermilion

* Fourcroy found the blood of a human foetus to
differ in three remarkable particulars from that of an
adult; viz. it contains no fibrous fubftance, ftriftly
fpeaking, but a fort of gelatinous matter ; it does not
take a bright colour from the conta(51: of air ; and it
does not afford any marks of its containing phofphoric
acid. The colour of blood is paler and thinner in infants,
in women, and in phlegmatic perfons, than in men of a
healthy and rebuff conftitution.

t Roueile's Analyfis,

in

Factitious Airs. 221

in blood that comes out of the, arteries, and
to the dark purple in blood that comes out
of the veins, but the latter, as has been ob-
ferved in the preceding pages, becomes
brighter by expofure to refpirable air. It is
not fo fluid as water, it feels unftuous or
faponacious to the touch, and has a little
fweetifh or faline tafle.

Soon after its extraftlon from the body,
as the blood cools and remains at reft, a
fpontaneous decornpofition, or feparation, of
parts takes place. A thick lump of coa-
gulated red matter is formed in the middle,
called the crajfamentum^ or clot of bloody and
a fluid of a flight greenifh yellow colour
furrounds it, which is called thtferum. The
quantity of ferum thus formed is lefs at
firft, than a few days after ; for as the coa-
gulable part contracts and grows harder, fo
more and more fcrum is forced out of it.

By wafhing the lum.p of coagulated mat-
ter, the colouring fubftance is entirely fepa-
rated from it, and the remainder is an in-

fi pid^

222 Medicinal Properties of

lipid, tenacious, white, and fibrous, fub-
ftance. The latter is called the coagulabk
lymph y ox fibrous matter^ of the blood. The
former, or coloured portion, when viewed
through the microfcope, is found to confift
entirely of feparate particles, circular and
pretty uniform in their fhape ; whereas the
feruni and the coagulable lymph, when ex-
amined with the befl tnicrofcopes* do not
appear to contain any diftind: particles in
their compofition.

The blood, therefore, confifts of, or is
firft of all refolvable into, three diftind:
parts ; namely, the ferum, the coagulable
lymph y and the red particles 3 each of which
is likewife a compound fubftance, but
whofe components cannot be fo eafily fepa-
rated from each other.

The fpecific gravity of human blood is
variable, but it always exceeds that of
water ; the latter being to the former, at
the leafl as one to i ,04, and at the moft as
one to 1,063. Each of its three principal

components

Factitious Airs. 223

components is likewife heavier than water;
but with refpedt to each other, the red par-
ticles are the heavieft, and the ferum is the
lighteft.

The ferum remains fluid in the ufual
temperature of the atmofphere, as far down
as a few degrees below the freezing point.
But it coagulates in a degree of heat about
equal to i6o** of Fahrenheit's thermometer-
The coagulation of ferum by heat is at-
tended with two peculiar circumftances,
viz. ill, a confiderable quantity of air is ex-
tricated from it in the adt of congelation ;
and, 2dly, a fmall part of it does not coagu-
late, but remains fluid.

The ccagulable lymph has been juflly
oonfldered as the moft important part of the
blood, and as being the fubftance, from
which all the other parts of the animal
body derive their increment and their fup-
port. The fibrous and tenacious nature of
this part, which th^ blood feems to derive
from the gluten of our food, is fo remarkable

that

224. Medicinal Properties of
that it may be ftretched out to a confi<lera-
ble length, and by the continuance of a
moderate degree of heat, it may be rendered
gradually more and more confiftent ; fo that
at laft it may be brought to equal the con-
fiftency of horn and even of bone.

Th e red particles, from which the whole
mafs of blood derives its colour, feem to
have no particular attradion for each other,
nor for the other two components, fo that
in the coagulum they are only entangled
and detained by the vifcid part. Their pe-
culiar and uniform Ihape has attracted the
attention of philofophers iince the latter
end of the laft century, about which time
they wxre firft difcovered. They have been
attentively examined with the beil: micro-
fcopes,and the appearances which have been
partly obferved and partly fuppofed, have
given origin to a variety of conjeftures and
hypothefes, generally fanciful, and often
abfurd.

When any thin and femitranfparent
part of a living animal, fuch as the tale of

a fmall

Factitious Airs. 225

a fmall fifh, the membrane which is between
the toes of a frog, Sec. is viewed through
a good microfcope ; the circulation of the
blood through its fanguiferoas veffels,. is
rendered manifeft anly by the motion of the
red particles, which follow each other at a
greater or lefs diftance ; though in general
each particle feems to touch, or, at leaft,
almofh to touch the following particle.
They never run into each other and incor-
porate ; and though not very hard, they
are however pofTefTed of a certain degree of
confiflency and elafticity ; for in pafling
through fmall veffels they are frequently
fctn to affume an elliptical ihape, and from
other fmaller veffels they are abfolutely ex-
cluded.

Those particles lofe their fhape, and are
diffolved in certain fluids. They are not
diffolved in the ferous part of the blood, nor
in urine, except when they are left in thofe
fluids for fome days, or when thofe fluids
are diluted with v/ater. But water is a
powerful, and almoft an inftantaneous. fv^l-
Q^ vent

226 Medicinal Properties of

vent of thofe particles ; yet v/ater may be
deprived of this property by the addition of
common fait, or nitre, or of almoft any
other neutral fait, as alfo by the admixture
of a very fmall proportion of vitriolic acid.

Marine acid nmch diluted v/ith water>
does not diffolve thofe particles> but it de- '
prives them of their colour.

Vinegar is likewife a folvent of the
red particles^ though not fo powerful as
water.

When thofe particle have been once
dried or diffolved in water, they cannot, by
any known method, be made to reaffume
their former fhape ; and indeed even their
formation in the animal body feems to be
dilEHcultly accomplifhed^ at leaft much lefs
expeditioufly than that of the other com-
ponents of blood ; for in perfons that have
loft much blood, the fanguiferous veffels
are indeed fpeedily £lled with new bloody
but this blood continues thin and pale for

aeon-

Factitious Airs. 227

a confiderable time, and if examined
through the microfcope, few red particles
will be found in it.

Unavilling to interrupt the account of
the chemical properties of blood, I fhall
referve the farther examination of the fhape
and fize of its red particles for the latter
part of this appendix, and fhall now fub-
join the farther analyfis of this fluid, which
is principally extracted from Fourcroy's late
chemical works.

Bloo©, expofed to a gentle and con-
tinued heat, paffes into the ftate of putrid
fermentation. When diftilled on a water
bath, it affords a phlegm of a faint fmell,
which is neither acid nor alkaline, but
eafily putrifies, in confequence of its con^
taining an animal fubflance difTolved through
it. Expofed to a more intenfe heat, blood
gradually coagulates and becomes dry ; it
then lofes feven-eighths of its weight, and
becomes capable of effervefcing with acids.
Deficcated blood, expofed to the open
Q 2 air^

228 Medicinal Properties of

air, attradls from it fome degree of moiiturev
and, in the courfe of a few months, there is
formed on it a faline efflorefcence, which
Jlouelle has determined to be carbonate of
foda. When diftilled by naked fire, it af-
fords a faline phlegm ; that is, a phlegm
holding in folution an ammoniacal fak, fu-
perfaturatsd with ammoniac. After this
phlegm, a light oil paiTes, then a ponderous
coloured oil, and ammoniacal carbonate
contaminated with a thick oil. There re-
mains in the retort a fpungy coal, very
difficult to be incinerated, which is found
to contain muriate of foda, carbonate of
foda, oxyde of iron, and a matter apparently
earthy, which feems to be calcareous phof-
phate.

Blood, when burnt in a crucible, affords
feveral products, in the following order:
1. water, and a little ammoniac; 2. oil,
and carbonate of ammoniac, which forms a
yellowilh vapour, thicker than the former;
3. Pruffic acid, which is eafily diftlnguiflied
by its foetid fmell of peach-flowers; 4. phof-

phoric

Factitious Airs. 229

phcnc acid, which is formed by the com-
buflion of phofphorus, and is not difen-
o:aeed till the blood be reduced to a coal ;
5. carbonate of foda, which is volatilized at
an intenfe heat ; 6. after this there remains
in the crucible only a blackilh, granulated,
cryftallized oxyde of iron, mixed with cal-
careous phofphate. The ferrugineous par-
ticles of this laft produd may be feparated
by the raagnet, efpecialJy v/hen the refi-
duum has been previoufly heated toge^
ther with charcoal-powder in a cpvered cru-
cible.

Blood combined with alkalis, without
previous decompaiition, becomes more fluid
by ftanding. Acids inftaptaneoufly coagu-
late it, and alter its colour. By filtrating
this fubilance, evaporating the liquor paffed
through the filter, drying it before a mo-
derate fire, and lixiviating the matter that
has been dried, neutral falts are obtained,
confifting of foda, with the acid that W4S
snixed with the blood.

0^3 If

230 Medicinal Properties of

If entire blood, mixed with a fourth
part of its weight of water, be coagulated
by heat, and if a part of the fluid that
fwims above the coagulated portion be eva-
porated, a fubftance of a brown yellow is
obtained, which is eafily diftinguiihed to
be true bile.

The ferum, which has been lately called
the albwninoiis fiuid^ communicates a green
tinge to fyrup of violets. By diftillation on
a water-bath, it affords a phlegm of a mild
infipid tafte, which is neither acid nor al-
kaline, but fpeedily putrifies. After lofing
this phlegm, it is dry, hard, and tranfparent
like horn : it is no longer foluble in water :
by difliliation in a retort, it affords an al-
kaline phlegm, a conliderable quantity of
ammoniacal carbonate, and a very foetid
thick oil. All thefe produdls, in general,
have a peculiar foetid fmell. The coal of
the ferum, when diftilled by naked fire, al-
Cioft entirely fills the retort. It is fo diffi-
cult to incinerate, that it muft be kept
burning for feveral hours, and expofed to a

great

Factitious Airs. 231

great deal of frefh air, before it can be
reduced to afhes. The aflies are of a
blackifli grey colour, and contain muriate
and carbonate of Ibda, with calcareous phof-
phate..

The ferum, if expofed for fome time to
an hot temperature in an open veffel, pafles
readily into a ftat«q of putrefaftioi?, and then
afFofds a confiderable quantity of ammonia
acal carbonate, with an oil, the fmell of
which is infufferably naafeous^

This liquor combines with v/ater in any
proportion, and then it lofes its confiftencyp
its tafte, its greenifli colour. When pour-
ed into boiling water, coagulates, almoft
wholly, inftantaneoufly. A portion of this
fluid forms, with the water, a fort of opaque
.and milky white liquor ; which, according
to Bucquet, poffefles all the charadleriftic
properties of milk, viz, it is rarified, and
caufed to mount up, by heat, and is coagu-
lated by the fame agents, viz. by acids, and
. by alcohol,

a.4 The

232 Medicinal Properties of

The ferum poffefles the property of
fixing and rendering folid by heat, two or
three times its weight of water. But when
the water exceeds feven times the quan-
tity of ferum, then no coagulation takes
place.

Alkalies render the ferum more fluid,
and acids coagulate it. This laft mixture,
filtrated and evaporated after fihration, af-
fords a neutral fait formed of foda and the
acid employed j which fhews that foda ex-
ifls in the ferum in a naked ftats, in full
poifeffion of all its properties. The coagu-
lum formed in this liquor by the addition of
an acid, is very fpeedily diffolved in ammo-
niac, which is the general folvent of the
albuminous part of the blood ; but it is not
diflbluble at all in pure water. Acids pre-
cipitate this matter in union with ammo-
niac. The coagulum affords, by diftillation,
the fame products as the ferum deficcated,
and its carbonaceous refidue contains a good
deal of carbonate of foda.

The

Factitious Airs. 233

The ferum, infpiiTated, affords azotic gas
by the adion of the nitric acid, with the
help of a moderate heat. On increafing
the fire, there is a quantity of nitrous gas
difengaged from the mixture.

The ferum does not decompofe calcare-
ous or alilminous neutral falts ^ but it ads
with fufficient energy in decompoiing me-
tallic falts.

This fluid is liable to be congealed by
alcohol : but this coag;ulum differs from
that formed by means of acids, chiefly for
its folubility in water.

The ferum, therefore, appears to be an
animal mucilage, confifting of water, aci-
-difiable oily bafes, muriate and carbonate of
foda, with calcareous phofphate*

The clot of the blood affords, by expo-
fure to the heat of a water-bath, an inlipid
water ; it becomes, at the fame time, dry
gnd brittle. It affords, in the retort, an al-
kaline

234 Medicinal Properties jf
kaline phlegm, a thick oil, of a foetid, em-
pyreumatic fmell, and a good deal of am-
fnoniacal carbonate. The refiduum which
it leaves, is a fpongy coal, of a fparkling me-*
tallic afpeft, difficult to incinerate, and af-
fording, when treated with fulphuric acid,
fulphate of foda and fulphate of iron ; there
remains, ;after thefe operations, a mixture
of calcareous phofphate with carbonaceous
matter. When expofed to a hot atmo-
fphere, the clot of blood readily putrifies.

When the clot is divided, by waflbing,
into its two principal components, viz. the
red part which is diffolved in the water^
and the coagulable lymph ; if the former
be treated with different menftrua it will
be found poffelTed of the fame charaderif^
tics with the ferum ; excepting that it con-*
tains a greater proportion of iron. The latter,
after being well waflied, will remain white,
colourlefs, and infipid. It affords, by diftil-
iation on a water-bath, an infipid phlegm,
without fmell, and liable to putrefadion.
Even the gentleft heat hardens this fibrous

matter

Factitious Airs. 23^

matter in a iingular manner. When ex-
pofed faddenly to a ftrong fire it flirinks
like parchment. By diftillation, in a retort,
it affords an ammoniacal phlegm, a pon-
derous oil, which is thick and very fetid,
and a good deal of ammoniacal carbonate,
contaminated with a portion of oil. The
refidual coal is not very bulky, but com-^
pad:, ponderous, and eafier incinerated than
that of the ferum. Its afhes are very white;
it contains no faline matter, as it muft have
loft, by the wafhing, whatever is contained
of that kind ; and no iron ; it is a fort qf
refidue of an earthy appearance, and feem-^
ingly calcareous phofphate.

The fibrous part of the blood putrifies
very quickly and eafily. When expofed to
a hot moift atmofphere, it fwells, and af-
fords a good deal of ammoniac. It is not
foluble in water ; when boiled in that fluid,
it becomes hard, and acquires a grey co-
lour.. Alkalies do not diflblve it, but even
the weakeft acids combine with it. The
nitric acid difengages from it a confiderable

quantity

^-6 Medicinal Properties of
quantity of azotic gas, and of Pruffic acid,
which comes out in vapour, and at length
diffolves it with eftervcfcence, and the dif-
engagement of nitrous gas. When it ceafes
to emit nitrous gas, the refidue is obferved
to contain oily and faline flakes, fwimming
in a yellowifh liquor : this liquor affords, by
evaporation, oxalic acid in cryftals ; and at
the fame time, depofits no inconfidera,ble
quantity of flakes, compofed of a peculiar
oil, and calcareous phofphate. It appears,
that hydrogene, carbone, and azote, which
cpnfl:itute the fibrous fubftance, are Sepa-
rated in different proportions, to combine
with the oxygen of the nitric acid, and
thus form the Pruflic and carbonic acids
that are difengaged in gas, and the oxalic
and malic acids, that remain in folution, an4
arc feparated only by cryftallization,

The fibrous matter diffolves alfo in th^
muriatic acid, which converts it into a fort
of green jelly. The acid of vinegar dif^-
folves it with the help of heat : water, and
cfpecially alkalies, precipitate this fibre us

matter

Factitious Airs. ^^j

matter from acids. This animal matter is de-
compofed in thefe com.binations ; and when
feparated, by whatever means, from acid?,
no longer exhibits the fame properties.

Thus much may fuffice with refpeft to
the chemical properties of blocd, I ihaii
now return to the examination of the con-
figuration of its red particles, with which I
iliall conclude this effay.

The red particles, w^hich form a very
fiTiall part of the human blood, were difco-
vered by means of the microfcope, towards
the end of the iaft century. They w^ere
found to be circular and uniform ; a tranl^
parent flat furface appearing to be fur-
rounded by a dark circumference. This
peculiar fhape feemed to indicate their be-
ing of Angular ufe to the animal ceconomy,
and excited the induftry of philofophers to
the further inveftigations of their lirudure.
As this could only be obtained w^ithout
ufing more perfed: microfcopes, and as
the perfj^dlon of microfcopcs depended

on

23S Medicinal Properties of
on the conftruclion of Imall lenfes, various
methods were contrived for the attainment
of this objedl, and niicrofcopical lenfes of
very fliort focufes, and of courfe of great
magnifying power, were foon produced;
but the utmoft power of thofe lenfes could
only difcover that when the panicles of
blood were magnified beyond a certain num-
ber of times, they exhibited a dark fpcck
in their middle, as a center to their circum-
ference.

This is all that could be clearly dif-
cerned in thofe particles by means of ground
lenfes ; but a vaft deal more was fuggefted
by the imagination; and it is curious to
obferve how much the eye and the under-
ilanding were deceived by the natural im-
perfedion of the inftruments, and by the
influence of premature theories.

Finding that the improvement of ground
lenfes, beyond the abovementioned power,
was obftrudted by weighty praftical diffi-
culties, the deficiency was attempted to be

fupplied

Factitious Airs. 1239

fupplled by the ufe of globules of glafs
made by melting ; for in the ftate of fufion,
the natural attra(flion between its particles,
will eafily form the glafs into a fpherical
body. Several methods were accordingly
devifed for conflructing thofe globules, as
may be feen in Dr. Smith's Optics, and
other publications ; but thofe methods are
either defedlive or abfolutely impradicable.
And, in fad:, I do not find that any globules
of very great magnifying power, were ufed
before the tim.e of Father della 'Torres who,
about the middle of the prefent century,
conftrufted globules of wonderful minute-
nefs, and at the fame time clear and dif-
tind.

This Neapolitan Friar, who, v/ithout
much fcientific knowledge, poilelTed a con-
liderable fhare of ingenuity, made many ob-^
fervations with thofe magnifiers, which he
publifhed, together with a minute and
faithful accountof his method of conftrudl-
ing the glafs globules, in a pamphlet, about
30 years ^go. But both the conftrudion
8 of

240 MEDicihJAL Properties of

of thofe globules, and their ufe as magni-
fiers, are very difficult ; fo that few perfons
have attempted to repeat Torre's experi-
ments, and amongft thofe, fewer ftill have
been fuccefsful. This want of fuccefs has
thrown a confiderable degree of fufpieion
en Torre's obfervations ; and as few people
are liberal enough to acknowledge their
v^ant of fufficient patience and addrefs, the
failure of the attempts has generally induced
people to confider Torre's aflertions in the
hght of miftakes or exaggerations. " The
" Abbe Torre," y^j/j- a recent writer^ ** ex-
*^ amined the red particles of blood with
** fimple lenfes, too ; but they magnified fo
** highly, that from this caufe all his noify
" mifcake has arifen; for he ufed not ground
" lenfes, but fmall fphericles of glafs, form-
" ed by dropping melted glafs into water :
" they magnified fo much that to him the
** central fpot appeared much darker ; he
** faid that thefe were not globules, but
" rings. He fent his fphericles of glafs,
** and his obfervations from Italy, his own
** country, to the Royal Society j and for a

** long

Factitious Airs. 241

*^* long while, though nobody could fee
** them, ftill the public were annoyed by
"Abbe Torre's rings V

Some years ago, when Torre's publica-
tion firft became known to me, I endea-
voured to conftrud: niicrofcopical globules
after his method, and to repeat his obferva-
tions. The undertaking, which at firft fight
appeared clear and eafy, proved on trial very
difficult and laborious ; hov/ever, after per-
fevering for a confiderable time, I at lafl
procured three or four ufeful globules cut
of a vaft number of imperfed: ones. With
thefe globules, and an apparatus made ex-
prefsly for fuch delicate experiments, I re-
peated feveral of Torre's obfervations, and
(as far as I now recoiled:, for both the
globules and the journal of obfervations
have been long fince loft) I found that his
defcription of appearances is very accurate,
though his conjedures may fometimes be
crude or miftaken.

* Bell's Anatomy, vol. ii. p. 89.

R Being

242 Medicinal Properties of

Being lately intent on the fubjed of
the prefent work, I was defirous to repeat
the above-mentioned microfcopical obfer-
vations, and for this purpofe I obtained,
after a confiderable expenditure of time
and labour, a few glafs globules, fufficiently
ufeful, and with them I made the obferva-
tions which I fhall now lay before the
public. But it will be proper to premife a
Goncife account of the principal opinions
that have been entertained by various: in-f
genious perfons, concerning the conftruc-
tion of the red particles, as the origin of
fome of thofe opinions will be evidently
pointed out by the obfervations that fol-
low.

Leeuwenhokck thought that each red
particle of the blood confifled of, and was
refolvible into, {\x fmaller globules, and
that tMti^ one of tliefe fecondary globules
confifted of other fmaller particles, Hew-
fontook them for bladders which contained
a nucleus or central body that feemcd to
roll from one fide of the bag to the other.

Tprrc

Factitious Airs. 243

Torre faw them like rings ; viz, confifting
of an internal and an external circle, and
this ring appeared to be divided, or to con-
fifl: of parts joined together like the rim of
a common coach v/heel. Falconer con-
sidered them as flat or fpheroidical bodies ;
for he thought he fometimes faw them fide-
ways. " The red globules," fays the late
Mr: J. Hunter^ '* are always nearly of the
** fame fize in the fame animal, and when
*' in the ferum do not run into one another
" as oil does when divided into fmall glo-
*^ bules in water. This form, therefore,
*^ does not arife iimply from their not unit-
*' ing with the ferum, but they have really
** a determined rtiape and lize. This is
** limilar to what is obferved of the globules
*^ in milk ; for milk being oily, its globules
" are not foluble in water ; neither do they
** confift of fuch pure oil as to run into
** each other ; nor will they difTolve in oiU
*' I fufped, therefore, that they are regular
"bodies, fo that two of them could not
** unite and form one *." Dr. Wells is of

* Treatife on the Blood, p, 41.

R 2 opinion^

244 Medicinal Properties of

opinion, that the fed globules confift of two
parts, one within the other, and that the
outer, being infoluble in ferum or dilute fo-
lutions of neutral falts, defends the inner
from the adion of thofe fluids ^.

Much having been faid againft the ufc
of microfcopical glafs globales^ efpecially
by perfons who had never feen them, I
thought it neceffary to afcertain the limits
of the fuppofed diftortion of the im.age, and
other imperfedions that had been attri-^
buted to them, and for this purpofe I viewed
certain objects of fimple or determinate
figures through lenfes and globules of
different powers, increafing gradually from
a magnifying power of about eight or ten
as far as that of about 400 times in lineal
-cxtenfion.

A DELICATE ftraight line made by
means of a diamond on a piece of glafs,
and which was quite inviiible to the naked

* Phil. Tranf.P.II. for 1797.

eye.

Factitious i\iRs, 245

eye, when thus gradually magnified, ap-
peared always ftraight, provided it was
made to pafs through the axis of the lens
or globule. The feathers of a butterfly, or
rather any particular part of one of thofe
feathers, never changed its figure though
magnified upwards of 400 times.

There is an evident diftortion of the
image when the objed: is viewed through
the edge of the lens, and efpecially of a
globule ; but no perfon verfed in fuch ex-
periments will ever obferve through the
edge of lenfes, though the lenfes be ever
fo perfedl.

V/hen the objedl is not very fiat, it is
then evident that a perfed: view of it ca.ri
not be had at once ^ for if one part of it be
in the focus, the reft of the objed: moft of
courfe be out of it 1 yet by alternately
bringing one part of the objedr and then
another to the focus, one m.ay, • in moft
cafesj acquire a fufficiently accurate id^ of
its (hape,

R 3 ^Varioifs

246 Medicinal Properties of

Various obfervations of this fort gave
me reafon to conclude that the glafs glo-
bules are by no means fo imperfedt as they
have been reprefented. Their diftortion of
the image is trifling and limited ; the tranf-
f arency of fome of them (and fuch only
Ihould be ufed) is equal to that of the beft
polifhed lenfes ; but the ufe of thofe glo-
bules is very difficult, and it is on account of
this difficulty that they have been negled:ed
and mifreprefented.

For the fake of thofe who may b@
willing to repeat fuch experiments, I fhall
barely mention the principal difficulties
which attend the ufe of the globules.

Their focus is confiderably nearer the
furface than that of a leris of the fame mag-
nifying powers and as a globule, in order to
magnify more than the ufual microfcopical
lenfes, muft be lefs than the 30th of an
inch in diameter, and its focus fhorter than
the hundredth part of an inch, it follows
that the common microfcopical apparatufes

are

Factitious Airs. 247

are in general inapplicable to fucli globules,
fince the deviation of one or two thoufandth
parts of an inch in the adjuitment of the
focus will occafion a confidcrable degree of
indiflindion.

It is for the fame r^afon, that the glo-
bule mufl be (ct fo as to have part of its
furface adlually out of the brafs cell, and
yet it mufl be fecured fo as not to drop
out.

The brafs cell mufl: admit of the globule
being eaiily taken out and replaced; for
v^hen they arc obfcured by duft:, &c. to
which they are very fubjedt, they can fel-
dom be cleaned without removing them
from the cell. — Let us now return to the
particles of blood.

I HAVE repeatedly meafured the diame-
ters of the red particles, both by means of
my mother-of-pearl micrometer in a com-
pound microfcope, and like wife by looking
at them with one eye through a lingle

R 4 lens,

248 Medicinal Properties of

lens, and referring their image to a fcale
properly divided, and viewed with the other
eye out of the microfcope.

In perfons of nearly the fame age the
mean lize of the particles differs very little
indeed. In the fame perfon they differ a
little, and their figure is not very circular.
This deviation from the circle is not fuch
as a flat circular furface would affume in
its diiferent inclinations to the axis of vi-
fion ; for, according to the rules of ortho-
graphic projedion, the fiat circular furface
muft appear either circular, or elliptical, or
as a ftraight line ; v/hereas I never faw the
particles of blood as ftraight lines, viz*
edgewife, and the elliptical figure, which
they fometimes afllime, is by no means re-^
gular.

In an adult of the human fpecies, the
diameters of the red particles run from
about 0,0003 to about 0^,0004 parts of an
inch, and I very feldom faw one fmaller or
larser than thofe limits. If, therefore, we

take

Factitious Airs. 249

take the fmalleft particles and fet them in a
row, we fliall find that about 3334 of
them will equal one inch, and if we take
the largeft, about 2500 of them will mea-
fure one inch.

When the particles are magnified more
than 40 or 50 times, and lefs than 80
(meaning always in diameter), they appear
like cclourlefs tranfparent fpots inclofed
within dark circle^.

When magnified more than 80 times,
and lefs than about 160, a dark fpot, like a
dot m.ade with ink on paper, appears in
the middle of each particle.

If the refleftor which illumines the par-
ticles, inftead of being fituated ftraight be-,
fore the object, be let on one fide of the
axis of vifion, fo as to throw the light ob-
liquely on the object, then the half of the
dark circle of each particle difappears, viz.
that half which is on the fide oppofite to the

rcfledlor.

250 Medicinal Properties of

rejfledtor. The central fpot does at the fame
time appear to change its place.

When the particles are magnified above
200 times, the central fpot appears con-
verted into a circle inclofing a tranfparent
fpace. The diameter of this inner circle is
about the half of that of the external one ;
but the proportion of thefe diameters, or the
fize of the internal circle, may be caufed to
increafe or decreafe by the leaft alteration
of the diftance betvs^een the objed: and the
microfcopical lens ; and by the fame means
the fpace within the inner circle may be
rendered clearer or darker than that be-
tween the two circles. The pofition of
the inner circle is changed by the dlre(5lion
of the light ^ for if the particle of blood be
viewed through a microfcopical globule,
diredly facing the flame of a candle, with*
out the intermediation of any lens or re-
fle<3:or, the inner circle will appear con-*
centric with the outer one ^ but if the
candle be moved a little to one fide, fo that
the light may fall obliquely on the particle

Qf

Factitious Airs. 251

of blood, then the inner circle will be ob-
ferved to move towards the oppolite fid«,
and to acquire an elliptical fhape.

When the particles of blood are magni-
fied above 400 times, an imperfedl image
of the candle, which is placed before the
microfcope, may be ken within the inner
circle of each particle.

Through a glafs globule of 0,018 of
an inch in diameter, I have fcen the red
particles of blood magnified about 900
times, in which cafe the image of the flame
of the candle could be ften w^ithin the in-
ner circle of each particle very clearly, at
leaft fo as to fhew to which fide the mo*
tion of the air in the room inclined it,

NoTV/iTHSTANDiNG this great magni-
fying power, the annulus or fpace between
the two circles did not appear to be di-
vided, excepting fome accidental fractures,
which now and then could be feen in a few
of the particles.

These

252 Medicinal Pr^perties^ of

These obfervations feem to prove, that
the red particles of blood are not perforated,
but that they are globular, and of fome uni-
form fubftance much lefs tranfparent than
glafs. They likewife jQiew that Mr. Hew-
fon's idea of their containing a central body
or nucleus, moveable within the external
fbell, arofe from the apparent change of
place which the various direftion of the
light produces on the central fpot or inner
circle of each particle. Warned, however,
by the example of other obfervers, I fliall
not attempt to oiFer any farther conjectures
concerning the nature and conftrudtion of
thofe particles. My reader may draw what
conclufion he thinks proper from the above-
mentioned fadts, and he may alfo, with
little trouble, fatisfy his curiofity concern-
ing thofe appearances, as I find that micro-
fcopical glafs globules miay be had at Mr.
Shutleworth's philofophical inftrament i3iop
on Ludgate Hill. I fhall therefore con^
elude with the account of a few experi-
ments which I have made, with a view of
imitating the phenomena that are exhibited

by

Factitious Airs. 1^53

by the particles of blood, the refult of
which feems to corroborate what has been
already obfcrved.

On the fuppofitlon of the red particles
beins: globular, I expe^Sed that globules of
other tranfparent matter would exhibit the
fame appearances as the particles of blood,
and my expe<5lations were in great meafure
verified by adlual experiments.

A GLASS globule was placed as an objed:
upon the ftage of the microfcope, and was
fucceffively viewed through lenfes of vari-
ous, but not great, magnifying powers. As
every part of the globule could not, be at
once in the focus, the whole of it was not
of courfe equally difi:in6l. This indiftinc-
tion, however, being not very great, I fhall
proceed without taking any farther notice
of it.

The globule appeared like a dark circu-
lar furface, with a tranfparent circular fpot
in the middle^ and in this fpot there ap-
peared

254 Medicinal Properties of

peared a diftindt image of the candle or
the window, or, in (hort, of any other ob-
jedt that was placed diredtly before it.

In this experiment three points of dif-
ference between the glafs globule and the
particles of blood were remarked, viz, ift,
that the globule ihewed a diftindl, whereas
the particle ihewed an indiftindt image of
the candle ; 2dly, that the inner circle of
the globule is much fmaller in comparifon
with its external boundary, than the inner
circle of the particle is in comparifon with
its external one ; and, 3dly, that the an-
nulus or fpace between the two circles is
uniformly dark in the glafs globule, whereas
in the particle it is about as clear as the in-
ternal furface, or rather clearer.

The firft and the laft of thefe points of
difference feem to depend ovi the imperfedl
tranfparency ®f the particles of blood; for in
femitranfparent bodies, whatever light falls
upon any part of them is fcattered through
the whole body.

The

Factitious Airs. 255

The fecond point of difference I attri-
buted to the particles of blood being fur-
rounded by a coagulated fluid of nearly an
equal refrafting power with themfelves,
whereas the glafs globule was furrounded
by air only. In order to verify this fuppo-
fition, I placed the glafs globule in water,
and viewing it in that ftate through the
fame magnifiers that had been ufed before,
I found that the tranfparent part or circle
appeared much larger than in the former
cafe ■*.

In the globule of glafs, as well as in the
particle of blood, the inner circle may be
made to appear larger or fmaller, by altering

* Thefe appearances are perfectly reconcileable to
the do£trine of optics. The light, which falls from &
luminous objedi: upon the glafs globule, illuminates at
moft one half of its furface, and in entering the furface
of the glafs, it is refracted towards the axis of the glo-
bule ; hence the whole cone of light being contra6ted,
muft pafs through a fmall part only qj^the oppofite fur-
face, and muft leave the reft deftitute of light. Now
tills contraction of the light muft vary according to the
difference between the refractive power of the globule
and that of th,e furrounding medium,

6 the

256 Medicinal Properties of, <S?r.

the diftance between the objedl and the
microfcopical lens.

In the glafs globule the inner circle may
be feen to move from the middle of the
dark furface, according as the candle is
moved from the dired: line betw^een the
objed; and the microfcopical lens.

INDEX.

INDEX.

/JERIAL fluids^ different fpecies of ^ page i— breathed
in combinations of three or four at a time^ 49— in*
je6i:ed into the cellular membrane, 51 — abforbed by wa-
ter, 56 — theory of, 58— their conftituent principles^ 67
- — ^how applied to the human body, 91, &c. 1 14 — remarks
concerningthe produ6lion of, 202 — prefervation ofj 209
— remarks concerning the adminiftration of^ 222,

Acidulous foda water, 145.

Jir^ common or atmofpherical, its propertieSj 2 — its purity
afcertained by means of nitrous gas, 3 — contains a va-
riety of fub fiances, 5 — vitiated various ways, 6— me-
thods of meliorating it, 6 — refpiration of, 23- — imbibed
through the pores of the fkin, 51— injeded into the
cellular membrane, 52 — its conftituent principles, 67—
decompofed in the lungs, 72— its various qualities^ 88,,

Animal heaty origin of, 82,

^-^//wfl/i^w, fufpended, treatment of, 116*

S Apparatus^

INDEX.

Apparatus^ neceflary for the produ(Si:ion of faditious airs,
90— for adminiftering the fadtitious airs, 91.

Afthma^ treatment of, 118.

A'Z'Otic gasy what, 6 — deleterious to animals, 48— injedled
into the cellular membrane, 52— inje6led into the ju-
gular vein, 53-^its conftituent principles, 67 — a diluent
of oxygen air, 87.

B.

Bag, oil filk, for containing air, &c. 92— -muft not be
folded. Sec. 212 — ^how to corredi: its bad fmell, 93.

Bladdersy for containing air, 94 — how to corredt their
bad fmcll, 95.

Bloody its colour altered by the prefence of different aerial
fluids, 53, 77— imbibes the oxygen in the lungs, 72, 76,
81 — its colour in the courfe of circulation, 78, 83, 220
—name of, 217— confifts of various ingredients, 219—
decompofition of, 221 — its fpecific gravity, 222.

C,

Cancery treatment of, 120,

Calculous complaintSy treatment of, 144.

Calorlcy what, 62 — laws relative to the communication of,
63 — capacity of bodies for containing it, 64—produces
a total change of properties in bodies, 66.

Capacity, for containing caloric, different in different bo-
dies, 64 — proportion of, in different bodies, 65.

Carbonic acid gaSy its properties, 15-^whence obtained, 16
— refpiration of, 46— appearances in the bodies of ani-
mals

I N D E X.

irials that have died in it, 47 — inje£ted into the cellular
membrane, 52 — inje£led into the jugular vein, 53 — its
pungency, 55 — an antifeptlc, 55, 102, in — how admi-
niftered, 56, 97 — its conftituent principles, 68— pro-
duced in the procefs of refpiration, 73, 85.

CafeSy medical j 149,

Gz/^rr^, treatment of, 123*

Chloro/iSy treatment of, 123.

Combuftioriy theory of, 69— analogous to refpiration, 75*

Confumptioriy treatment of, 124.

Coughs^ treatment of, 130,

CraJJamentumy or clot of blood, what, 221.

D.

Debility^ treatment of, 1 30.
Dsphlogijiicated atr^ the fame as oxygen air, r»
Digejiion^ impaired^ treatment of, 133,
i)r<9^, treatment of, 135.
Dyfpepfta,, treatment of, 133.

E*

Eudiometer^ ivhat, 3.
Eruptions, treatment of, 136.
Ethery its ufe, no.

F.
Fever Sy treatment of, 137*
Fixed airy the fame as carbonic acid gas, t,

S 2 H,ad^

INDEX.

H.

Head'Och^ treatment of, 141.

Heaty its origin, 62, 66— animal, whence derived, 82,

Hamoptyfis^ treatment of^ I4£.

Hydrocarbonate^ what, 19 — refpiration of, 45—remarks
concerning the production of, 207.

Hydrogen gas ^ 'its properties, 17 — whence obtained, 18— -
refpiration of, 42, 44-— properties of its various fpecies,
43 — injeded into the cellular membrane, 52— -it does
neither accelerate nor retard putrefaction, 55 — its con-
flituent principles, 67 — remarks concerning the pro-
duction of, 205, 208 — contains extraneous particles,
206 — apt to degenerate, 210.

I.

Inflammable air^ the fame as hydrogen gas, 2.
Inflammation^ of the lungs, how treated, i©7, 109, 118.

Lime-water^ ufe of, 210.

■ •

Langs, human, affeded by the fmalleft differences in the
purity of the air, 4, 214.

Lymph of blood, 222, 223.

M.

Manganefe yields abundance of oxygen air, 14, 202— it
generally contains calcareous earth, 203 — 'fliould be
made quite dry before it is ufed, 205.

'MuMth'piece^ ufed for breathing any particiilar fort of
air, 96.

N. Nitrous

INDEX.

N.
NltTdus gasy diminiilies common air, 2 — 'dimlniihes oxygen
air, 10,

O.

Oil-fill hagSy ufeful for refpiring particular airSj 92— Isow
to remove their oily fmell, 93,

Ophthalmia^ treatment of, 142.

Oxygen alr^ its properties, 9— obtained from various fub-
flances, 9, 11 — diminifhedin various circumftances, 10,
14 — refpiration of, 29- — its ftimulant quality, 34, 35,
36, 37, 54, loi — efFe£ls produced by it when diluted
with common and other airs, 34, 38, 40 — imbibed
through the pores of the fkin, 51 — inje6ted into the cel-
lular membrane, 52 — its conftituent principles, 67 — in-
difpenfably neceffary to animal life, 74 — when to be
adminiflered, 102, 104.

Oxygenation^ of metals, 69 — of blood, 72.

P.

Paralyfis^ treatment of, 143.
Phlogijiicated air^ what, 6. , ^

Phlogijlon^ what, 60.
Phofphuret of hydrogen^ what, 19.
Phthifis^ treatment of, 124.

Red particles of blood, 222, 224 — opinions concerning
their conftrudionf 242 — microfcopicai appearance of,
249 — their diameter, 248.

Refpiration of common air^ 23— of oxygen air, 29 — of
other fa<^itioiis airs, 40-— theory of, 58, 71.

Scurvy^ treatment of, 143.

£erim of blood, 221, 223.

4 , Skin.^,

INDEX.

Sktn^ the aerial fluids are imbibed and expelled through ltd

pores, 51.
Specific gravities of the aerial fluids, 20— table of, 21 —

effects arifing from it, 4.9.
Stone in the bladder, treatment of, 144,
Sulphur et of hydrogen, 19.
Swellings^ treatment of, 146.

T.

7Beoryy of aerial fluids, 58 — of refpiration, 59, 60, 72.

U.

Fejfels^ proper, for the produdion of aerial fluids, 204— for

the prefervation, &c. 209.
Ulcer Sy treatment of, 147.

W.

IFaier abforbs aerial fluids, 56 — its confl:ituent principles,
68-^expelled from the lungs, 73 — origin of, in the
lungs, 85 — how impregnated with carbonic acid gas, 98

JFhitifwdlingy cafe of, 146.

THE END,

Works fuhlijhed hy tU fame Author.

I. A Treatise on the Nature and Properties of
AIR, and other permanently elaftlc Fluids ; to which
is prefixed, an Introdudlion to Chemiftry. Quarto, with
Plates.

II. A Treatise on ELECTRICITY, m
Theory and Pra<5lice5 with original Experiments. The
Fourth Edition, in Three Vols. 0(S^avo, with Plates.

III. The History and Pradice of A E R O S TA-
T I O N, Oaavo, with Plates.

IV. A Treatise on MAGNETISM, in
Theory and Pra6lice ; with original Experiments. The
Second Edition, O£lavo, with Plates.

V. Two Mineralogical Tables, with an Ex-
planation and Index.

VI. Description and Use of the Telefcopical
Mother-of-Pearl MICROMETER, invented hy
the Author.

^ The following Dire£iIons are added for the In-
formation of fuch Readers as may be willing to try the
Factitious Airs, or may otherwife wifli to promote the
Subjea of this EfTay :

Mr. Watt's Apparatus for the ProduCtiorij &c. of
Factitious Airs, is fold at Chippindall's Birming-
bam Warehoufe, in Salifbury-Court, Fleet-Street.

The Artificial Airs, accurately preparedj are fold
in any Quantity by J. Rance^ No. 30, Clipftone-Streetj
Fitzroy-Square.

The Acidulous Soda Water, containing an ex-
traordinary Quantity of Carbonic Acid Gas, is fold at
Schweppe's Artificial Mineral Waters Manufadiory,
No. 1 1, Margaret- Street^ Cavendifh- Square.

.The Microscopical Glass Globules, fuch as are
mentioned in the Appendix, are fold by H. Shuttle-

worthj Cptician^ on Ludgate-Hill.

zr. f

XI. L. 47-